MK350 Series

Survival Handbook

Table of Contents

Introducon . . . . . . . . . . . . . . . . . . .1

Common Types of Arcial Lighng . . . . . . 2

Incandescent Lighng . . . . . . . . . . . . . . . . . . . . . . . 4

Fluorescent Lighng . . . . . . . . . . . . . . . . . . . . . . . . 6

LED Lighng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Advantages & Disadvantages . . . . . . . . . . . . . . . . . . .12

The Market . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Where does light come from? . . . . . . . . 18

Atoms Make Light . . . . . . . . . . . . . . . . . . . . . . . . . .20

How does an Incandescent Bulb make light? . . . . . . . . . . .24

How does a Fluorescent Light makes light? . . . . . . . . . . .26

How does an LED make light? . . . . . . . . . . . . . . . . . . .28

Fluorescent Yellow . . . . . . . . . . . . . . . . . . . . . . . . .30

Why LEDs use Semiconductors? . . . . . . . . . . . . . . . . . .32

How does light work? . . . . . . . . . . . . . 34

Famous Experiment 1 . . . . . . . . . . . . . . . . . . . . . . .34

Famous Experiment 2 . . . . . . . . . . . . . . . . . . . . . . .36

Wave Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . .40

See Light or Sense Light? . . . . . . . . . . . . . . . . . . . . .44

So what is color? . . . . . . . . . . . . . . . 46

Reecon, Absorpon, Transmission . . . . . . . . . . . . . . .48

Color Wheel - Mixing colors . . . . . . . . . . . . . . . . . . . .50

Rods & Cones . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

Measuring Light . . . . . . . . . . . . . . . . 54

Using Temperature to measure light color? . . . . . . . . . . .56

How does a device measure light? . . . . . . . . . . . . . . . .58

Matching Wavelengths to Colors . . . . . . . . . . . . . . . . .60

The Chromacity Diagram - CIE 1931 . . . . . . . . . . . . . . .62

How the Chromacity Diagram Came About . . . . . . . . . . .64

Wavelength Intensity . . . . . . . . . . . . . . . . . . . . . . . .69

How does a light meter determine x,y? . . . . . . . . . . . . . .70

The Color wheel and the Chromacity Diagram . . . . . . . . .72

CIE 1931 to CIE 1976 . . . . . . . . . . . . . . . . . . . . . . . .76

MK350 Series - Things you should know . . . 78

Diracon Grang . . . . . . . . . . . . . . . . . . . . . . . . .81

Cosine Correcon . . . . . . . . . . . . . . . . . . . . . . . . . .82

Dark Calibraon . . . . . . . . . . . . . . . . . . . . . . . . . . .84

Measuring Fluorescent Light with MK350 . . . . . . . . . . . .86

Half Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . .87

Planckian Locus . . . . . . . . . . . . . . . . . . . . . . . . . . .88

Rundown of Unit Measurements . . . . . . . . . . . . . . . . .90

Recognizing Dierent Wavelength Spectra . . . . . . . . . . . .92

Applicaons . . . . . . . . . . . . . . . . . . 94

Light and Agriculture . . . . . . . . . . . . . . . . . . . . . . . .96

Measuring PAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98

PPF Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99

Lighng Designers . . . . . . . . . . . . . . . . . . . . . . . .100

Dialux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Measuring LUX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Cool vs Warm - Color Temperature . . . . . . . . . . . . . . . . . . . . . .106

Correlated Color Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Duv ∆u ∆v ∆y ∆x . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Light Health and Safety . . . . . . . . . . . . . . . . . . . . . . 112

Measuring UV Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Measuring Harmful Blue Light . . . . . . . . . . . . . . . . . . . . . . . . .114

Measuring Flicker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116

Lighng Road & Trac . . . . . . . . . . . . . . . . . . . . . . 120

Measuring LED Degradation . . . . . . . . . . . . . . . . . . . . . . . . . .120

Measuring Trac Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Measuring Light in Hospitals . . . . . . . . . . . . . . . . . . 123

Surgical Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Replacing LEDs in Jumbo Screens . . . . . . . . . . . . . . . . 125

Tesng and Calibrang LED Based screens and Monitors. . .126

sRGB, AdobeRGB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

Lighng Store Display . . . . . . . . . . . . . . . . . . . . . . . 130

Lighng Academics & Research . . . . . . . . . . . . . . . . . 132

Research - Measuring Surface Colors . . . . . . . . . . . . . . . . . . . . .134

LED Heat Sink Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Research Publishing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

LED Professionals . . . . . . . . . . . . . . . . . . . . . . . . . 138

Research and Development . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

Light Exhibitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Appendix 1 - CIE 1931 in-depth . . . . . . . 144

Bibliography . . . . . . . . . . . . . . . . . 148

The overwhelming ood of LED lighting in the market is undeniable – LEDs are energy efcient,

longer lasting, cooler, shockproof and non-toxic and this is why this guide will focus on LEDs.

However, there are challenges to LED lighting - namely, that LED light quality and color can be quite

inconveniently unpredictable.

Therefore, you need measuring equipment to gauge LED light quality. However, light is about

physics and precision equipment and is highly specialized, bulky, expensive and for the most part

impractical. This is where the MK350 Spectroradiometer makes its timely entry into the market, a

hand-carry, cost-effective light meter that provides precision light measurement outside the connes

of laboratory space and into our everyday working and living environments.

It’s the Question that drives us ...

Why the MK350 Survival Handbook?

The MK350S series devices are designed to measure the quality of light. As simple as that may

sound, understanding the importance of good lighting and how the MK350 devices work can be quite

challenging. This handbook is a survival guide to help you through the complexities of light science

and to teach you the great advantages of MK350 technology.

This handbook …

■ is customized for learning the MK350 devices, light and lighting

■ is easy to follow (like a “Dummies” Book)

■ theoretically requires no prior knowledge

Our Goals

■ Goal 1 - Fast Track to MK350 knowledge

■ Goal 2 – Become a Lighting Expert

■ Goal 3 – #1 Customer Service/Sales Force

Introduction

- The Matrix -

Incandescent

■ Commercial use - mid 1900s

■ Uses lots of energy

■ Generates heat - hot to the touch

■ Needs to be replaced often

■ Shatters easily

■ Light quality is very consistent

and close to the quality of Sun

light.

KMJ, alpha masking by Edokter - GFDL - CC-SA-3.0 Wikimedia Commons

Common

Types of

Articial

Lighting

Let’s rst discuss the 3 common

types of Lights:

Incandescent Lighting

Fluorescent Lighting

LED Lighting

The traditional Incandescent bulbs

were rst on the scene . Next,

came the Fluorescent Lights and

then LED Lights, both bringing

advantages in bulb lifespan and

energy savings. However, they are

all three, still in use with their own

distinct advantages and disadvan-

tages.

ONE

Thomas Edison did NOT invent the Incandescent Bulb ...

but he did make it commercially viable!

Fluorescent

■ Commercial use - 1930s

■ Cool to the touch

■ Lasts longer than Incandescent

■ Uses less energy than Incandes-

cent

■ Still shatters easily

■ Contains dangerous mercury -

poses a hazard when broken or

during normal disposal.

LED

■ Commercial use - Early 2000s

■ Cool to the touch

■ Lasts longer than Fluorescents

■ Uses less energy than Fluorescents

■ Does NOT shatter

■ LED quality is not consistent

during production and needs to be

classied and sorted at different

quality levels after production.

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TWO

THREE

Common Types of Articial Lighting

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MK350 Series Survival Handbook

Incandescent Lighting

Incandescence

uses heat (thermal radiation) to

produce light. Sunlight and

Candle-light are generated in

this way. Incandescent Light

Bulbs also generate heat (ther-

mal radiation) through a “la-

ment” - the lament heats up to

produce light like a candle.

uses heat to make light ...

The great advantage is that

this type of light quality and

color is generally very consis-

tent between most brands. Its

color qualities are also very

close what the Sun produces.

The great disadvantage is that

this type of bulb requires lots of

energy which is wasted as dis-

sipated heat (90%). Also, the

intense heat causes faster degra-

dation of the lament leading to

a shorter lifespan of the bulb.

Tungsten Filament

Electrical Foot Contact

Foot Base Contact

Tungsten is a hard metal that

doesn’t melt or degrade easily,

and so it makes a good material

for a lament.

Halogen lights are a type of

Incandescent Light but contain

Halogen gas inside the bulb to

slow down degradation of the

lament, allowing it to with-

stand more heat, and making it

suitable for high intensity lights

(e.g. car head lights).

TELL ME MORE

Heat means Lifespan

Incandescent Lighting

KMJ, alpha masking by Edokter - GFDL - CC-SA-3.0

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By 4028mdk09 Creative Commons Attribution-Share A like

3.0 Unported

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MK350 Series Survival Handbook

Fluorescent Lighting

Image: © Nevit Dilmen found at Wikimedia commons - CC-BY-SA-3.0

uses UV radiation to make light ...

Fluorescence uses light (or

electromagnetic radiation) to

make light - it’s related to phos-

phorescence (watches).

TELL ME MORE

Image by I, Autopilot - CC BY 2.5 Generic Wiki-

media Commons

Arc Lamp - Fluorescent Lights

are a type of Arc Lamp that pro-

duces light, typically through a

non-conductive medium, like

air. Lightning is similar, a type

of natural Arc Lamp.

Ziemor at pl.wikipedia - CC-BY-2.5-Generic

Fluorescent Lights have been

commercially available since

the 1930s as long Fluorescent

Tubes. A smaller bulb-like

CFL (Compact Fluorescent

Light) only became widely

available in the 2000s.

These lights use a mercury

vapor (steam) inside the tube;

electricity is applied within the

tube, which causes the mercury

vapor to emit UV light, or more

accurately UV radiation. The

UV radiation hits the inside sur-

face of the tube which is coated

with a phosphor material. The

UV radiation causes the phos-

phor to glow.

Their advantage is that they

are cooler and more energy

efcient than Incandescent.

Their disadvantage is that

Mercury is dangerous - if the

bulb is broken, it can present a

health hazard. Used bulb dis-

posal is also problematic.

1.Electricity warms the tube.

2.Mercury turns to vapor.

3.Vapor is excited by further elec-

tricity and UV light is emitted.

4.UV light hits the inside surface

of tube, which is coated with Phos-

phor material, which then glows

(emits light) - i.e. Using light (UV

light) to make visible light.

Fluorescent Lighting

Christian Taube, White Balance Deglr6328 - CC-BY-SA 2.0 - Germany

Sun Ladder - CC-BY-SA-3.0

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MK350 Series Survival Handbook

LED Lighting

Early LEDs (Light Emitting

Diodes) were used mainly for

small indicator lights for ap-

plications like display panels -

they have been used in this way

since the 1960s and they looked

like the bulbs at the top of this

page.

During the early 2000s, we

began to see LED technology

used for environment lighting

as well (e.g. homes, ofces, fac-

tories, schools) and LED bulbs

began to look much like our

Circuit Board Pro-

cessor made from

semiconductor

material

Early LED bulbs (from 1960s)

LED strips used for tube lighting.

Mcapdevila - Multi-license CC-BY-SA-3.0 and GFDL -

Wikimedia Commons

Afrank99 - CC-BY-SA-2.0 Generic Wikimedia Commons

uses semiconductors to make light ...

traditional light bulbs. They

even produced LED strips to

look like Fluorescent Tubes.

LEDs use semiconductors.

Yes, it’s similar to the material

used on processors for circuit

boards. However, the materials

used in LEDs are for the pur-

pose of producing light.

In addition to being cooler and

more energy efcient (like

Fluorescent Lighting), LEDs

have an added value of lasting

a VERY long time, in addition

to being shatter/shock proof.

As you can see from the early LED lights,

the semiconductor is a very small compo-

nent. The semiconductor itself produces a

bluish-white light and the lens/case chang-

es the color to t the application. More

recent LEDs might appear as below, but

the same semiconductor principles apply.

Modern LEDs may look like this ... or like this ...

Anode

Cathode

Epoxy lens/case

Semiconductor die

or like this ...

LED Lighting

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MK350 Series Survival Handbook

LED Lighting

LED lights work when elec-

tricity is run through the semi-

conductor die, which makes it

produce a bluish light.

Notice the yellow layer on top

of the semiconductor - it chang-

es the semiconductor’s bluish

light to become more of a com-

fortable white light - sometimes

A closer look ...

this yellow layer is referred

to as the Fluorescent layer or

Phosphor layer.

The LED may have a lens on

top to redirect the light to ob-

tain uniform overall intensity.

Cathode

Semiconductor Die

Phosphorescence vs. Fluores-

cence

Both use “light to make light”.

However, phosphorescent material

does not immediately re-emit the

radiation it absorbs.

Die or Diode - these words may

sometimes be used in place of

LED chip or semiconductor chip.

LED Package - this is the entire

housing (i.e. package) for the

LED.

Fluorescent Layer

LED chip

Lens

Anode

Package

Fluorescent

TELL ME MORE

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MK350 Series Survival Handbook

Advantages & Disadvantages

Practically and economically speaking, LEDs seem to have a huge advantage and this is why

most newly built facilities in developing countries are choosing LEDs for most of their envi-

ronment lighting (e.g. factories, ofces, libraries, museums).

So why continue

to buy Incandescent

Lights?

For the consumer, it is the

out-of-pocket expense that is a

signicant factor. A retail LED

(as of this writing 1/2014) may

cost $15 out-of-pocket but an

Incandescent bulb may cost

you only $3. Which would you

buy? What if you had to re-

So why continue

to buy Fluorescent

Lights?

Fluorescent Lights fall between

Incandescent and LEDs. It lasts

much longer than an Incandes-

cent light, but it’s cheaper than

an LED light.

It’s ideal for places that are

not assured a long term loca-

tion (e.g. for a convenience

store that is renting space, why

would you buy a 50,000 hour

LED light?).

CC-BY-SA-2.5 Generic - NoAuthorListed

place 2 bulbs ($30 vs $6).

The Incandescent light also

comes as close to natural sun-

light compared to the other two,

and its light quality is close

to Sunlight, which is the gold

standard for light because, as

evolutionary beings, our eyes

have become accustomed to

sunlight and the rich colors it

produces.

Life Span (average)

Watts of electricity used

(equivalent to 60 watt bulb)

Kilo-watts of Electricity used

(equivalent to 30

Incandescent Bulbs

per year)

Annual Operating Cost

(equivalent to 30

Incandescent Bulbs

per year)

50,000 hours

6-8 watts

3285 KWh/yr

767 KWh/yr

329 KWh/yr

$ 32.85 /year

$ 76.65 /year

$ 328.59 /year

60 watts

13-15 watts

1,200 hours

8,000 hours

Advantages & Disadvantages

Why people still use incandescent bulbs (USAtoday 12/27/2013)

http://www.usatoday.com/story/news/nation-now/2013/12/27/incandescent-light-bulbs-phaseout-leds/4217009/

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MK350 Series Survival Handbook

Disadvantages ...

The fragile Fluorescent tube

can easily shatter and presents

a health hazard when the toxic

Mercury liquid is exposed;

clean up requires careful, me-

ticulous removal procedures.

Mercury exposure is known to

cause neurological problems.

The most troublesome aspect of

incandescent lights is its indis-

criminate use of energy.

90% of the energy used is dissi-

pated as heat - only about 10%

is released as light.

LEDs use semiconductors -

though you may think this type

of technology is quite sophis-

ticated, the actual production

of the LED chip is not always

an exact science - LED light

quality can vary quite greatly

between batches and each batch

may be categorized and sold as

different qualities of color and

intensity.

Fluorescent Lights use UV light

inside their tubes, but small

amounts do escape - UV light is

harmful to the eyes and skin.

Fluorescent Lights have also

been known to Flicker - studies

indicate that long term exposure

to light icker is harmful to our

eyes.

Fluorescent Light - Health Issues

LED lights

Not all LED chips are created equal

In fact, CPUs used in com-

puters are also semiconductor

based and have similar issues -

they cannot guarantee the same

exact performance from batch

to batch and measures must be

taken to moderate performance

expectations (e.g. over-clock-

ing).

Incandescent Light

http://www.designrecycleinc.com/led%20comp%20chart.html

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MK350 Series Survival Handbook

The Market

■ There are still lots of people who use incan-

descent lights (mostly in homes).

■ There are still lots of Fluorescent Lights in

public places (e.g. hospitals, ofces etc.).

■ Lighting designers are saying new facilities

(factories, hospitals, libraries etc.) are most

likely to install LEDs.

G’bye to Incandescent

Countries exercising full, partial, planned bans of incandescent bulbs or exchange programs.

(according http://en.wikipedia.org/wiki/Phase-out_of_incandescent_light_bulbs as of this writing 02/2014)

Hello to LED

Estimated North American LED market to grow about 45% every year over the next 7-8 years.

A changing world - What we know

Bottom Line:

LEDs are on course to take

over the world.

■ Some existing facilities are changing out

their lights completely for LEDs, already

realizing the long term cost savings.

■ Most developed countries are exercising

phase-out plans for use of incandescent

bulbs.

■ The price of an LED bulb is dropping to the

point that they will start to compete with

CFLs for market share and eventually sur-

pass them in a few years (maybe by 2015).

The Market

Original by Ukelay33 - GFDL- CC-BY-SA-3.0 - Adapted for this topic

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MK350 Series Survival Handbook

The importance of

understanding light.

Understanding the basics of what light is and where

light comes from is the key to understanding LED

lighting and MK350 devices. However, we must rst

get our feet wet in the world of Science, particularly

Physics and Chemistry. This section explains the

lighting fundamentals in layman terms, in a straight-

forward, concise and practical way, without any

MATH!

Before we begin, we must set some expec-

tations. Physics and Chemistry are like

Magic - there are things you will see that

will amaze and confound you at the same

time. So it’s important to prepare yourself

to turn your world upside-down and be

ready for anything.

A little Science and Magic ...

Dispersive_Prism_Illustration_by_Spigget.jpg: Spigget, derivative work: Cepheiden (talk)

CC-BY-SA-3.0 Generic - Wikimedia Commons

Turning your world

upside-down

Where does Light come from?

Where does light come from?

1918 MK350 Series Survival Handbook

Light

Molecular

Structure

Determines

Color

Texture

Smell

Weight

Conductivity

and more ...

What is an atom?

Light comes from atoms, so we need to rst under-

stand what an atom is. Everything is made of atoms.

The table, the wall, your cell phone, oxygen ... even

you. Actually, an atom is so small that you can’t really

see one - but, when you combine them together, they

become things, like water.

What is a molecule?

Atoms in an object are usually arranged into groups

of atoms called molecules. For example, if I take one

Oxygen (O) atom and add two Hydrogen (O) atoms, I

get an H

O molecule. These atoms are attracted together

by forces (electrostatic forces). Many molecules form

an object - sometimes these molecules are loosely held

together like water, or sometimes they are tightly held

together like metals. It all depends on the molecular

structure.

Oxygen Atom

Molecules determines, like DNA determines

Your DNA determines your physical characteristics; your gender; how tall,

how heavy, the color of your hair. In a similar way, Molecular structure

determines an object’s characteristics; its color, its texture, its smell , its

weight, ability to conduct electricity, melting temperature etc. Metal is sol-

id, water is liquid - it’s all because their molecular structures are different.

Dschwen - CC-BY-SA-2.5 Generic Wikimedia Commons

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dia Commons

One Oxygen Atom and

Two Hydrogen Atoms

O Molecule

Many H

O molecules

become water

P99am - Creative Commons Attribution-Share Alike 3.0 Unported

Molecular Structure of

Aluminum

It’s Like

Atoms Make Light

2120 MK350 Series Survival Handbook

Light

Electrons are the Key

It’s Like

Let’s take a closer look ...

Making light from an atom is an easy

process. You just need a little imagination.

Inside an atom, there is a large nucleus -

then there is a small electron (s) that ies

around the nucleus in a xed orbit - you

can think of it as the Sun (nucleus) with the

smaller Earth (electron) orbiting it. When

energy is thrust upon the atom, the electron

ies out to a higher orbit. When it returns

to its original (natural) orbit, light is emit-

ted.

1. The electron ies around in its natural orbit.

2. Energy can be added which causes the electron to

move to a higher energy orbit for a short time.

3. The electron returns to its lower natural orbit and

light (photons) is released (energy released).

4. The electron remains in its natural orbit, until it is

excited again into a higher orbit and the process

repeats itself.

Making Light of Things

Nucleus -The Nucleus of an

atom contains neutrons and

protons. Protons are positively

charged, Electrons are nega-

tively charged and Neutrons are

neutral (no charge).

TELL ME MORE

Atoms make Light

2322 MK350 Series Survival Handbook

Light

How does an

Incandescent bulb make light?

Inside an Incandescent bulb, electricity

is used to heat up the Tungsten Filament.

The electrons in the Tungsten Filament

begin to jump out to a higher energy orbit

for an instance and then drop back to its

natural orbit, releasing light.

Electrons are the Key

How does an Incandescent Bulb make light?

Tungsten Molecule

2524 MK350 Series Survival Handbook

Light

How a Fluorescent Light makes Light

1.Electricity warms the tube.

2.Mercury turns to vapor.

3.Vapor excited by further electric-

ity and UV light is emitted.

4.UV light hits the inside surface

of tube, which is coated with Phos-

phor material, which then glows

(emits light) - Using light (UV

light) to make light (visible light).

How does a Fluorescent Light makes light?

UV Light

Electron

Visible Light

Electron

Mercury Vapor Atoms

Phospor Atoms

UV Light

As we mentioned, a Fluorescent Light makes light in

two separate steps; electricity causes mercury vapor

to emit UV light, the UV light strikes the Phosphor

inner lining and causes the Phosphor to emit visible

light. In both cases, the same mechanisms of Ener-

gy-Atom-Electron-Photon are in effect.

2726 MK350 Series Survival Handbook

Light

Energy

How does

an LED make light?

Electron movement in Semiconductors

As we saw on the previous page, electrons at higher orbits

that drop back to lower orbits, release photons of light. In

LED semiconductors, a similar strategy is at work.

Electrons jump from higher energy states to lower energy

states.

LED semiconductors have two layers. The top semiconductor

layer, called n-type, is modied to have extra free electrons.

The bottom layer, called p-type, is also modied, but to have

positively charged “electron holes” (but not really “holes”,

more like pockets), which can attract free electrons.

When current is passed through these two layers, the elec-

trons and holes move toward each other - when an electron

is close enough to a hole, it falls into it, going from a high

energy state to a low state (hole) and as we already know,

this releases a photon.

Negative free electrons in n-type layer

and positive holes in p-type layer are in a

steady state.

Current is applied from top to bottom - the

positive holes moves toward the negative

pole of current, electrons move toward the

positive pole.

As an electron (at a higher energy state)

passes a hole, it falls into it (lower energy

state). The release of energy emits a pho-

ton of bluish color.

Electrons are the Key

Cathode

Die

Lens

Anode

How does an LED make light?

www.youtube.com/watch?v=BH9LI973H8w

Watch a Video

2928 MK350 Series Survival Handbook

Light

Fluorescent Yellow

Different materials used for the semiconductor will produce different wavelengths of light -

however, if LEDs use AsGaAl, the resulting light will be bluish, which would not fare well as

a white light. So, on top of this type of semiconductor you will nd a yellow lm. This lm is

made from a Yellow Fluorescent Powder - but don’t think of it as just a lter - it makes light by

itself. If you remember how Fluorescent Lights work - they use UV light to make light. It’s the

similar process with LEDs.

This blue light causes the electrons in the Fluorescent Layer to move to

a higher orbit. When the Fluorescent electrons return to a normal orbit,

a yellow photon (light) is emitted. The blue light is still transmitted

through the lm, but mixes with the yellow light to produce a white

light (we’ll talk more about mixing lights later).

Fluorescent Layer

LED chip

Lens

Fluorescent Layer

Resulng White Light

Semiconductor

Fluorescent Film

Energy causes the semiconductor electrons to emit blue light.

1. The blue light, emitted from the semiconductor, excites the electrons in the Fluorescent

lm to a higher orbit. The electrons then return to their natural orbit, emitting a yellow

light.

2. This yellow light mixes with the blue light (which still is coming from the semiconduc-

tor) to make white light - this process is called “color mixing”, which we will talk about

later.

Blue + Yellow = White

Fluorescent Yellow

3130 MK350 Series Survival Handbook

Light

Why LEDs

A suitable material

for LEDs

Early experiments (around

1955) found that low levels of

infrared light could be detect-

ed when running an electrical

current through Gallium Arse-

nide, a semiconductor material.

Throughout the years, other

materials have also been added

(e.g. Nitrides, Aluminum) to

further upgrade the viability of

semiconductors as a practical

LED light source

Doping can add free electrons

Doping can add more Electron Holes

Why is the Semiconductor light blue?

LED semiconductors are known to produce a blu-

ish light. The color of light from any atom de-

pends on how far the electron falls from its higher

energy state - the farther the fall, the more ener-

gy released and the higher the frequency of light

(low frequency = more reds, higher frequencies =

more blue). Aside from AlGaAs, other materials

such as Indium, Phosphide, Nitrides, Silicon, are

used because their molecular structure can pro-

duce other colors of light.

More Red

Electron

More Blue

Electron

The Rubber Band Experiment - Pull a rubber band apart and let go of one

end - notice the sound of the snap. Now pull a rubber band farther apart and let go,

and notice the louder sound (ouch!). The farther apart means more energy released.

use Semiconductors?

Perfecting LEDs

Actually, pure AlGaAs is a poor

conductor of electricity - how-

ever, you can add impurities, a

process called “Doping”. Dop-

ing adds more free electrons

to the semiconductor material

(n-type). You can also use

Doping to create more electron

holes in the material (p-type).

This entire process of making

semiconductors is not always

an exact science, and the nal

product is not always predict-

able.

Why not use plastic?

Why not use wood, glass, cot-

ton or plastic? It’s because of

the molecular structure. In some

materials it is difcult to ma-

nipulate the electron because of

the electron’s attachment to its

nucleus - if you can’t move an

electron, you can’t create light

from it.

Molecular Structure Determines

Why LEDs use Semiconductors?

W. Oelen - CC-BY-SA 3.0 Unported Wikimedia

Commons

3332 MK350 Series Survival Handbook

Light

How does light work?

What is a Rainbow?

The rst famous experiment

was performed by Isaac New-

ton . Basically, he was able to

simulate the phenomenon of

rainbows and in doing so he

made an important discovery.

Light is made of many

different colors.

Newton pointed a light beam at

a prism. The light, as it went

through it, bent or refracted and

separated the light into different

colors. It basically proved that

light is made up of many colors.

In a rainbow, the clear rain

droplets act as small prisms,

also dispersing light into differ-

ent colors.

Refra

ction

Refraction or bending of light

occurs when light enters an-

other medium and slows down.

The light disperses (separates)

Why does light bend, as it passes

through a prism? Think of refrac-

tion as a car entering water at an

angle.

Weblars - Creative Commons Attribution-Share Alike 3.0 Unported - Wikimedia Commons

Two famous experiments ...

The right tire hits the water rst

while the left keeps going at the

same speed. The angle of the car

begins to turn or “bend”.

because of the different wave

frequencies of color bend at dif-

ferent angles (we will talk about

light waves later).

It’s Like

Famous

Experiment 1

Famous Experiment 1

How does light work?

3534 MK350 Series Survival Handbook

Light

Agustin Ruiz CC-BY-2.0 Generic - Wikimedia Commons

When you drop two stones (at a

distance) in a pond of water, two

rings of waves emanate from the

center of both drop-points. When

two wave peaks meet (red circles),

the resulting wave peak is a bigger

wave equal to the two wave peaks

added together. The interesting

part is that when the 2 waves pass

each other, they go back to their

original form.

In a more controlled two-slit exper-

iment, Young sent an initial water

wave through 2 slits on a front wall.

Two separate waves were created at

each slit opening. They interacted

with each other and eventually hit

another back wall. When the waves

interacted they created super-sized

wave peaks where they intersected -

these high wave peaks impacted the

back wall at the same place creating

bands of force with each band rep-

resenting the intersection of the two

waves. This is how water waves

work.

Back Wall

Two slits

Front Wall

Initial wave

Maximum Force Bands

Famous

Experiment 2

Early researchers were fairly

certain that light was made of

particles, because of the way

that light bounces off of things

like walls or even mirrors - like

a ball.

However, a famous experiment

called the Double-Slit Experi-

ment was performed by Thomas

Young in the early 1800s. It

proved that ...

Light also behaves like

waves.

Young understood how water

waves worked. Let’s look at the

stones-in-a-pond example.

Is Light particles or waves?

Famous Experiment 2

3736 MK350 Series Survival Handbook

Light

Let’s try the same idea using light.

Since we think that light is particles, we

can expect the photon particles to hit

the back wall with only two bands (as

shown above).

Back Wall

Two slits

Front Wall

Light Source

Maximum Force Bands

However, when Young tried this exper-

iment, to his surprise, he saw the same

wave banding against the wall - light

behaves like water waves too! He

couldn’t actually see “waves” of light,

however it was the result

that was convincing. So light

behaves both as particles and

waves!

Back Wall

Two slits

Front Wall

Light Source

Maximum Force Bands

What

Expected & Got

http://www.youtube.com/watch?v=DfPeprQ7oGc

Watch a Video

3938 MK350 Series Survival Handbook

Light

Wave behavior

Remember that when two wave

peaks meet, they make a su-

per-sized wave? Another phe-

nomena occurs when a peak

passes over a trough - they cancel

each other out - and when they

pass each other, they revert back

to their original forms.

The basic idea is that several

waves can exist at the same time

and place, change each other,

while still being distinct.

Super-sized waves - 2 peaks meet

Canceling waves - 1 peak meets 1 trough

In our pond wave examples,

both of the two waves were

basically the same size.

However, there are two other

things that also make waves

different, which are frequency

and wavelength. Wavelength is

the distance from one peak to

the next.

Frequency is the number of

peaks that pass a xed point

(Start Point) in a xed amount

of time. In the rst example, 4

peaks travel past a xed point

in one second - the frequency is

4 cycles /sec.

The second example has a fre-

quency of 2 cycles per second.

Which wave travels faster?

Two waves can

exist in the

same place,

same time and

still be distinct

“

Wave Behavior

All light, no maer the frequency, travels at the same speed.

4140 MK350 Series Survival Handbook

Light

Weblars - Creative Commons Attribution-Share Alike 3.0 Unported - Wikimedia Commons

So now we know that light

behaves like waves. Why does

light disperse going through a

prism? There must be some-

thing different for the different

colored waves in white light.

Can you guess?

English Wikipedia (Original author : Philip Ronan)

- GFDL - CC-BY-SA-3.0 Generic

Light is considered electro-

magnetic radiation, which is a

general term that includes all

visible and invisible sources of

electromagnetic waves, ranging

from UV light, x-rays, visible

waves, infrared to radio waves.

As you see above, the Visible

Light is only a very small por-

tion of that.

This much we know - all forms

of electromagnetic radiation

carries energy.

Frequency and wavelength.

Each color inside white light

has a different frequency and

wavelength and this is what

causes each to bend slightly

differently.

Blue light slows down more

than red light and will therefore

bend more than red light.

Since light behaves like waves,

several colors can exist at one

time in one beam of light and

still maintain a distinctive wave

shape.

1st prism

2nd prism

Color Spectrum

white light

... And the really cool thing is that you can

combine the different colors back into white

light, which really convinced authorities that

light is composed of many colors.

4342 MK350 Series Survival Handbook

Light

See Light or Sense Light?

You are standing in a dark

room. There is a ashlight on

the left pointing to a wall on

your right.

For Your Eyes Only

You don’t really “see” light -

because light is invisible.

You sense light

when it hits your eye as

waves of energy

and it’s only then that it

stimulates your

brain to make a picture

of what is in front of you,

very much like

a camera.

1. I can see light if I look left, directly into it.

2. I can see light if I look right, directly at the wall.

3. However, if I look straight ahead, I cannot see the light traveling

in front of me. Why not?

See Light or Sense Light?

4544 MK350 Series Survival Handbook

Light

Let’s continue with Sir Isaac

Newton’s exploration into light

and color. As we discovered,

light from the Sun is a compos-

ite of different colors.

Newton also established that

the colors that we see on objects

(e.g. apples) are not attached to

those objects - the colors come

from an original light source.

In other words, nothing inher-

ently has color - just turn off

the light and you will “see”.

Nothing “has” Color

So what is color?

What happened to blues, greens, yellows?

The red that you see in the

apples come from the original

light source, the sun, which re-

ects off the apple and reaches

our eyes.

So what is color?

4746 MK350 Series Survival Handbook

Color

When light comes from a source

and hits an object, three things can

happen:

Reection

Absorption

Transmission

It makes sense to wear white in

hot, sunny regions. Why?

TE Lawrence - Lawrence of Arabia

Joergbieszczak - Creative Commons Attribution

Share Alike 3.0 Unported

Black absorbs all light and makes the cat warm.

Reection, Absorption,

Transmission

Absorbed

Ref lected

Transmitted

Incident

Reection is when the light (e.g. red light) reects off a

surface. A white surface reects all light.

Absorption - This is what happened to the other colors in

the apple example on the previous page. The blues, yellows,

greens were absorbed by the apple! The absorbed energy

turned to heat in the apple. A black surface absorbs all light

and this is why black is referred to as the absence of light.

Transmission - This is what a prism does, it lets the light go

through (with a little refraction/bending).

The apple reects red and absorbs the

rest of the colors.

Reection, Absorption, Transmission

Dance of Light

4948 MK350 Series Survival Handbook

Color

Good Readings

So, we know that white light is made up of

different colors as Newton discovered. He also

conceptualized the rst color wheel. This color

wheel has evolved over time and has come to

show us how colors interact and mix with each

other to form new colors.

The concept of primary colors was derived from

the color wheel, identifying a few basic colors

that could make up all of the other colors. For

RGB color wheel

Color Wheel - Mixing colors

OK, so we can mix two or three colors of equal

amounts to get a resulting color. The diagram on

the right is another way of showing a mixture of

colors - it is from a white light source. Howev-

er, light is not just two or three separate colors,

but a continuum of colors all connected together

into what we call a spectrum (like a rainbow).

There is another element and that is the amount

of a certain wavelength or the intensity or bright-

ness (y-axis). Notice that there is a green and

an orange spike - this shows that the orange and

green waves coming from this light are brighter

(more intense) than the other colors. This type of

diagram is called a color spectrum.

Primary Colors

red+green+blue=white

White

Opposite colors make white

(blue-yellow)

White

Additive vs. Subtractive

We use these two terms to describe

how to mix colors. The additive

method is used with light - you add

different colored lights together to

make your desired color. Subtractive

method is used with surfaces where

you start with a light and use a sur-

face to absorb (subtract) from the

light and reect the remaining colors

to form the new color. RGB is addi-

tive and CMYK is subtractive.

Spectrum - a continuum of colors,

like the rainbow

Spectral Colors - all the colors

visible to humans

TELL ME MORE

computers, they use red, blue and green. From

these 3 colors you can make all of the colors that

you can see on your screen. All of the colors in

the RGB color wheel can be made with just those

3 colors. Red + blue make the Secondary color

purple. Secondary + Primary colors make Tertiary

colors and so on. Red + green + blue make white

(in the middle). Also opposite colors such as blue

+ yellow also can make white (sound familiar?

hint LED light + Fluorescent Light).

Red

Blue

Purple

blue+red=purple (magenta)

Color Wheel - Mixing colors

www.colormatters.com

5150 MK350 Series Survival Handbook

Color

http://www.youtube.com/watch?v=UXIfzc1UH-g

Rods & Cones

As we mentioned, light waves can enter

our eyes. In the back of our eye is the

retina - the retina has photo-receptor cells

(cells that can receive and act on light

waves) - These photo-receptors are called

Rods (night) - Scotopic Vision

Cones (day) - Photopic Vision

These Rods and Cones process light and

send impulses through the Optic Nerve to

our brain, which form an image IN OUR

MINDS.

The Rods are used in low light conditions

and do not visualize colors well. The

Cones however, are used in sunlight or

lighted conditions and can process colors

more effectively. Cones are mostly con-

centrated in the Fovea, a small depression

in the Retina.

There are 3 types of cones that were rst

Electromagnetic Wave

S-Cones

M-Cones

L-Cones

Rods

Ji-Elle- Creative Commons Attribution-Share Alike 3.0 Unported

Our colors are inherently a human experience

thought to process red, green and blue wavelengths and

mix them together to form all colors, conveniently just

like our RGB color wheel - but that was too good to be

true. A more apt and recent naming convention is S, M,

L cones because each cone processes a range of Small,

Medium and Large wavelengths - however, they are

sometimes still habitually referred to as red, blue and

green cones.

These cones actually overlap each other when process-

ing color from light (see below). It’s even more com-

plicated the further down the processing you go, as we

shall see.

Optic Nerve

Cones

Rods

Rods & Cones

http://www.youtube.com/watch?v=V73k_0KuUJo

Watch a Video

Ji-Elle- Creative Commons Attribution-Share Alike 3.0 Unported Wikimedia Commons

Patrick J. Lynch, Medical Illustrator, C. Carl Jaffe MD - CC-BY-2.5 Generic

Wikimedia Commons

OpenStax College - CC-BY-3.0 Unported

5352 MK350 Series Survival Handbook

Color

Measuring Light

Why measure light?

A light bulb’s light quality can

vary signicantly and people

are discovering that it can in-

uence us emotionally, phys-

ically and even economically.

Light affects the way we work,

the way we feel and even the

way we sleep and wake.

However, these aspects of light

that affect our lives are not eas-

ily seen by the human eye and

we need a measuring device to

help us see things that we can’t

normally see.

Also, as humans, our eyes are

not all the same and the colors

we see may be slightly different

or even quite different than how

others see them. We can use a

light meter to help us agree on

colors.

Traditional light measurement

equipment is expensive, immo-

bile, complicated and requires

By Electro Optical Industries Uploaded by The

Lamb of God at en.wikipedia -

CC-BY-SA-3.0 Wikimedia Commons

By Cmglee - Creative Commons Attribution-Share Alike 3.0 Unported

Superman Eyes

inordinate setup time including

the manpower needed to run

just one test on a single light

source. The main part is called

an Integrating Sphere and it

is still the most sophisticated

equipment for measuring light.

The idea of the inner sphere is

to provide a controlled environ-

ment for uniformly scattering

light and accurately measuring

the results.

The MK350 device is also a

light measuring device. Al-

though it admittedly cannot

compare with the integrating

sphere in terms of a controlled

and pristine environment, the

MK350 has shown remarkable

Photometry is the science of mea-

suring light

Spectrophotometry - measurement

of ux and spectral distribution.

TELL ME MORE

light measurement accuracy in

open space environments and

it’s practical uses and econom-

ic advantages make it nothing

short a revolutionary advance-

ment in light measurement

devices.

A light meter helps you see what you can’t normally see

with your own eyes.

Measuring Light

5554 MK350 Series Survival Handbook

Color

Measuring Light

You may nd it strange that

white light color can be spec-

ied by a temperature - a bulb

may have a Color Temperature

of 2700 Kelvins - but there is a

close relationship between tem-

perature and light.

When you heat up an object like

an iron horseshoe, it begins to

slowly glow red, and then turn

yellow, and then white and nal-

ly blue. The cooler the tempera-

ture the more red; the hotter the

temperature the more blue (op-

posite of what we might think).

This relationship is important

because it’s a way to objectively

measure color - this relationship

was explained by Max Planck in

his famous Planck’s Law. An

LED bulb’s Color Temperature

(CT) is 3000K, means that when

you turn on the bulb, its light

has the same color as an iron

horseshoe (for example) heated

to 3000K.

Of course, the amount of heat

to make something glow red-

yellow-blue-white will vary

somewhat on the matter being

Using Temperature to measure light color?

Incandescent Lights are based

on heat as we learned and are

natural Black Body Radiators

and so Color Temperature can

be specied quite accurately.

CFLs and LEDs are based on

Mercury Gas/Phosphor and

Semiconductors and so the CT

can only be approximated with-

in a certain range - these ranges

are called the Correlated Color

Temperatures, which can be

notoriously misleading (we’ll

explain why later).

Color Temperatures and Black Body Radiators

used (e.g. horseshoe). So a

theoretically, ideal matter was

conceived called the Black

Body - a perfect absorber,

absorbing 100% of light and

thus making it a perfect emitter

of heat radiation. Nothing is

really a perfect absorber, but

many objects that radiate light

using heat come close - the Sun,

a candle, an incandescent light.

Color Temperature is only

applicable to lights and in

lighting design it helps us to

gauge how cool or warm we

want our environment to look.

Generally, Color Temperatures

(CT) around 5,300K are called

cool colors (bluish white),

while lower color temperatures

around 3,300 K are called warm

colors (yellow to red). It is said

that people in hot tropical re-

gions prefer buying bulbs with

CT over 5,000K (to make it feel

a like a cooler bluish environ-

ment), while people in cooler

northern or southern regions

prefer bulbs with CT below

3000K (warmer-reddish looking

colors).

Warm Light

Around 3300K or below

Neutral Light

Around 3300K~5300K

Cool Light

Around 5300K or above

Using Temperature to measure light color?

By “Hi-Res Images of Chemical Elements” Creative Commons - Wiki-

media Commons Attribution 3.0 Unported

5756 MK350 Series Survival Handbook

Measuring Light

How does a device measure light?

So, we’ve seen how to use

temperature as a reference for

measuring color. However, it’s

only a theoretical model (Black

Body), used to measure white

light and it is very imprecise

with CFL and LED lighting. So

there must be another way of

measuring light.

Let’s take another look at

“Color”. Color, as we see it, is

inherently a human experience

- blue skies, red apples, green

trees form as images in our

brains. A device has no way

to sense “blue”, as much as it

cannot sense “sadness”, be-

cause “blue” and “sadness” are

How does a machine

know what colors

to display on a screen?

By the numbers.

inherently human experiences.

Devices, however, can measure in numbers - take your scale for

instance, which measures in kilograms or pounds. Light is the

same - a light meter device can measure light by its numbers -

i.e. wavelength, frequency and intensity. We can use these num-

bers to relate waves to our visual colors and an easy way to do

this is to use the primary colors of red-blue-green, conveniently

similar to our S, M and L cones. In other words, we can teach

our device to use RGB to relate “our” colors to wavelengths.

Yellow, what is yellow?

Waves? What waves?

How does a device measure light?

M.Minderhoud at nl.wikipedia - GFDL, CC-BY-SA 3.0 Unported - Wikimedia Commons

5958 MK350 Series Survival Handbook

Measuring Light

First, we need to take a light

with a certain wavelength, and

then have a tester adjust in-

tensity values of red, blue and

green lights to match the test

color to relate the wavelength

to human color perception.

This gives us 3 values (RGB)

to represent each color wave-

length that we want to test.

However, since we all see

colors a little differently, we

need to include many testers,

record their data and then take

an average.

Matching wavelengths

to colors

Take the data, which is in sets of 3 RGB values per

wavelength and graph it on a 2D plane - this graph

makes the connection between wavelengths and

RGB values that humans perceive. For a Wave-

length of 580 (yellow), we see that equal parts of

Red and Green are used (circle on graph).

These tests were real experiments performed

in 1926 by William David Wright and John Guild.

The Matching Function

Step

Matching Wavelengths to Colors

Test color - 580nm

100%

R 700nm

G 546.1nm

B 435.8nm

r g b

380 0.0272 -0.0115 0.9843

385 0.0268 -0.0114 0.9846

390 0.0263 -0.0114 0.9851

395 0.0256 -0.0113 0.9857

400 0.0247 -0.0112 0.9865

405 0.0237 -0.0111 0.9874

410 0.0225 -0.0109 0.9884

415 0.0207 -0.0104 0.9897

420 0.0181 -0.0094 0.9913

425 0.0142 -0.0076 0.9934

430 0.0088 -0.0048 0.9960

435 0.0012 -0.0007 0.9995

440 -0.0084 0.0048 1.0036

445 -0.0213 0.0120 1.0093

450 -0.0390 0.0218 1.0172

Step

Oh, that’s yellow!

This device can use the

matching data we just cre-

ated. When it encounters

a wavelength of 580 nm, it

can adjust its RGB screen

lights and display the prop-

er color on its screen.

6160 MK350 Series Survival Handbook

Measuring Light

It’s Like

The Chromaticity Diagram

Identifying, Specifying and Comparing Light

OK, we’ve taught our light meter to

recognize colors. Now, it would be

nice to be able to take a measure-

ment of any light source and then

identify it, specify it and perhaps

compare it to other lights.

We do this with a color map called

the Chromaticity Diagram (Chroma

is the Greek word for color) and it’s

an important part of a light meter.

It’s like a map of our globe - if you

know the Longitude and Latitude,

you can identify any place on Earth.

Similarly, if you know your x,y col-

or coordinates, you can nd where

your light color lies compared to all

the other colors we can see - and by

the way, the colors contained within

the map are all of the colors humans

can visualize and this map is called

Chromaticity Diagram.

NY - Broadway and 42nd Street

40 45’ 21” N latitude

73 59’ 11” W longitude.

The Chromaticity Diagram - CIE 1931

Fuzzypeg at en.wikipedia, derived from Paulschou at en.wikipedia - CC-BY-SA-3.9

Measuring your light source identies where your

light lies in the map of x,y coordinates.

x,y

6362 MK350 Series Survival Handbook

Measuring Light

How the Chromaticity

Diagram Came About

How the Chromaticity Diagram Came About

r g b

380 0.0272 -0.0115 0.9843

385 0.0268 -0.0114 0.9846

390 0.0263 -0.0114 0.9851

395 0.0256 -0.0113 0.9857

400 0.0247 -0.0112 0.9865

405 0.0237 -0.0111 0.9874

410 0.0225 -0.0109 0.9884

415 0.0207 -0.0104 0.9897

420 0.0181 -0.0094 0.9913

425 0.0142 -0.0076 0.9934

430 0.0088 -0.0048 0.9960

435 0.0012 -0.0007 0.9995

440 -0.0084 0.0048 1.0036

445 -0.0213 0.0120 1.0093

450 -0.0390 0.0218 1.0172

How do we come up with these

x,y coordinates and the map?

Well, it’s a long story with lots

of math, but we’ll try to keep

it simple. This Chromaticity

Diagram was conceived in 1931

by the International Commis-

sion on Illumination or more

commonly referred to by its

French acronym CIE or the

Commission Internationale de

l’Eclairage.

It was designed to map the

entire human visible spectrum -

it gives us a standardized, easy,

visual tool to specify, identify

and compare colors. Do you

remember our RGB test val-

ues from before? We plotted

them on a 2D graph as shown

(top right). Now what we want

to do is put those same RGB

values on a 3D graph. Each

wavelength’s RGB data were

mapped as a point in 3D-Space

which produced the diagram

on the right, a beautiful but

not very useful map. So the

CIE folks did some fancy work

to make a 2D map, from a 3D

map.

Remember when the three RGB test values are plotted on a 2D

graph? It looks like the graph below.

If you plotted all of the RGB test values onto a 3D graph, then you

would get this. It’s hard to use a 3D map for color identication

because your color might lie in the middle.

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

.5, .5, 0

.33, .33, .33

0, 0, 0

.5, .5, 0

1,1,0

1,1,1

1,1,0

1,1,1

Let’s rst draw a 3D space. Each axis represents one of the primary col-

ors of Red, Blue and Green. The ends of each axis represent the highest

intensity from the each RGB test data set, which we will show as 1.

6564 MK350 Series Survival Handbook

Measuring Light

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

.5, .5, 0

.33, .33, .33

0, 0, 0

.5, .5, 0

1,1,0

1,1,1

1,1,0

1,1,1

Now let’s plot our yellow wave-

length (580 nm), which is full red,

full green and no blue (1,1,0)

Let’s take our “White”, which is a

combination of 100% Red, 100%

Green and 100% Blue and plot that.

Imagine doing this for all our RGB

points for each wavelength.

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

.5, .5, 0

.33, .33, .33

0, 0, 0

.5, .5, 0

1,1,0

1,1,1

1,1,0

1,1,1

Next (this is the magical part),

make a triangle by connecting 3

three points that each represent

100% intensity at each primary

color (RGB) - this is a plane called

the Unit Plane - if you take a single

point on the plane and add up the

three associated data values, they

will always add up to 1. If you

draw a line between each RGB

point that we plotted (in step 3) and

the origin (0,0,0), it intersects our

Unit Plane and creates a new point.

This point represents the same pro-

portions as the original point and so

it is essentially the same color.

Now imagine all the wavelength

RGB points mapped to the Unit

plane - what will you get? A

horse-shaped Chromaticity Dia-

gram!

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

.5, .5, 0

.33, .33, .33

0, 0, 0

.5, .5, 0

1,1,0

1,1,1

1,1,0

1,1,1

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

.5, .5, 0

.33, .33, .33

.33, .33 .33

.5, .5, 0

1,1,0

1,1,1

1,1,0

1,1,1

6766 MK350 Series Survival Handbook

Measuring Light

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

.5, .5, 0

.33, .33, .33

0, 0, 0

.5, .5, 0

1,1,0

1,1,1

1,1,0

1,1,1

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

.5, .5, 0

.33, .33, .33

0, 0, 0

.5, .5, 0

1,1,0

1,1,1

1,1,0

1,1,1

Since our Unit Plane is a 2D

plane, we can now assign it an x,y

axis. This is where the horse-shoe

shaped CIE Chromaticity Diagram

comes from.

Take Home

1. The horseshoe shaped diagram is a

“map” all of the colors that human

beings can visualize.

2. If you measure a light source, it can

give you an x,y coordinate which tells

you where in our map your light color

resides

3. The x,y coordinates are derived from

data from the original 1926 RGB

Human Experiments. They represent

RGB data values that have been math-

ematically condensed from 3D to a 2D

plane because it is much easier to work

with.

NOTE

The previous explanation is a conceptual description of the

creation of the Chromaticity Diagram. For additional informa-

tion see Appendix I

http://www.youtube.com/watch?v=82ItpxqPP4I

http://www.biyee.net/color-science/cie-chromaticity-diagram/

Watch a Video

Play

Wavelength Intensity

Now we know that a device like an MK350 can capture a single light source and separate it into

its different component wavelengths. Each component wavelength inside the light could have

different quantities of “intensity”, which inuence the color. This is represented by the Color

Spectrum (below-left) also provided by the MK350 devices. It shows the different wavelengths

and their respective intensities. In this example, we can see that reddish colors at about 610 nm

are dominant and will cause the white light to appear perhaps reddish - however, you must really

take all the colors and mix them together to really know if your light is more reddish, greenish or

bluish - and that is what the x,y point on the Chromaticity Diagram can tell you. Chromaticity

Diagrams show you color; the Color Spectrum shows you the intensities of all the wavelengths

that, when mixed together, make up that color.

Wavelength Intensity

Color Spectrum

Weblars - Creative Commons Attribution-Share Alike 3.0 Unported - Wikimedia Commons

6968 MK350 Series Survival Handbook

Measuring Light

How does a light meter determine x,y?

1. A light meter captures light

2. Separates the light into distinct wavelengths

3. Sends each wavelength data through the Color Match-

ing function to gure out how humans see these wave-

lengths in terms of Reds, Greens and Blues.

4. For each wavelength, it then “mathematically” plots

the RGB values for all those wavelengths in 3D space

and “mathematically” normalizes it to 2D (Unit Plane

or x,y plane).

5. It takes all those points and adds them together to ar-

rive at a single x,y coordinate.

6. Finally it plots it on the Chromaticity Diagram!

■ a way to objectively specify, identify and compare light sources

■ derived from Human Data Experiments (1926)

■ derived from RGB, a convenient model for mixing colors; it is convenient because it is like our 3

Cones which are loosely based on RGB.

■ used to map x,y coordinates that represent a light’s chromaticity (color) among all the colors humans

can see and agree on (standardize colors)

■ used by a light meter like the MK350 - it captures light and goes through all the necessary steps to

arrive at an x,y coordinate for a light source

■ all the colors visible to the human eye

Chromaticity Diagram

Color Spectrum

Take home - The CIE 1931 Chromaticity Diagram is ...

Weblars - Creative Commons Attribution-Share Alike 3.0 Unported

Mathematical Calculations

Color Matching Functions

Separate Colors in Light

7170 MK350 Series Survival Handbook

Measuring Light

Color wheel and the Chromaticity Diagram

Remember our original

color wheel? Our Chro-

maticity Diagram has

characteristics that are

similar in some ways.

Like mixing and match-

ing colors to make new

colors.

In our Chromaticity Diagram,

you can mix n’ play like our

color wheel. If you take a point

that is red and you connect it to

a blue point, the midpoint will

be purple. Similarly, mixing

blue and yellow gives you

whitish color - however these

midpoints will not generally be

accurate because of distortions

in the diagram.

Reddish

Purplish

Yellow

White

RGB color wheel

Red

Blue

Purple

Opposite colors make white

(blue-yellow)

White

If your color is at x,y and you

drew a line from the white

point to the outer edge, you will

arrive at a fully saturated color,

or the “dominant wavelength”

(e.g. 560) - it’s like taking your

x,y color and taking all of the

white out of it.

Somewhere close to the middle

of the gamut there is a white

point, which is at .33 and .33.

This is an important reference

point.

x,y

Bluish

White point

Fully Saturated Color

The Color wheel and the Chromaticity Diagram

7372 MK350 Series Survival Handbook

Measuring Light

All of the dominant wave-

lengths on the outer contour and

are also all the monochromatic

(pure) colors that can be repre-

sented by one wavelength and

are also all the colors split up

by our prism (all the rainbow

colors).

At the bottom of the “horse-

shoe” is a straight line. It is

called the “Line of purples”.

These are real colors that we

can see but with one exception -

they are not pure colors, mean-

ing a single wavelength cannot

represent any color on that line

(unlike 700 nm wavelength that

represents pure red); you need

to mix two or more colors to

produce them.

Line of Purples

Pure Colors on

the contour.

(this page left intentionally blank)

7574 MK350 Series Survival Handbook

Measuring Light

CIE 1931 to CIE 1976

The CIE 1931 was the original

Chromaticity Diagram followed

by, CIE 1960 and CIE1976,

which were improvements to

their respective predecessor

- but change doesn’t always

come easy - CIE 1931, is still

in widely used. The most

recent CIE 1976 version boasts

improvements that more ac-

curately matches our visual

perception compared to the CIE

1931 diagram.

All the colors in the CIE 1931

diagram are supposed to be

distinguishable colors. Exper-

iments by Kodak researcher

David L. MacAdam along with

GNU Free Documentation Creative Commons Attribution-Share Alike 3.0 Unported

CIE 1976 specication actually includes two versions; the CIELAB

and CIELUV. They both take into account the distortions revealed

by the MacAdam’s Ellipses. Furthermore, these also take into

account more recent revelations in how our 3 cones really process

colors (see below). Like CIE 1931, CIELUV and CIELAB have x,y

coordinates, but use u,v and a,b respectively

Another advantage to CIELAB and CIELUV is that they have

a larger color space and are device independent - what does this

mean? It means that you can choose a logo color and not have

to worry about CMYK, RGB, sRGB, Adobe RGB, Pantone - the

devices will adapt to CIELAB. However, change comes slow and

this is why lots of devices are still stuck on CIE 1931, not wanting

to comply with CIELAB.

The difference between CIELAB and CIELUV is usage. CIELAB

is recommended to be used for subtractive processes used in print-

ers, while CIELUV is recommended for use with additive processes

like displays (monitors).

Creative Commons Attribution-Share Alike 3.0 Unported - googolplexbyte

Opponent Color Theory

Better but still not perfect

Deane B. Judd and Gunter Wyszecki

provided empirical evidence that CIE

1931 represented a distorted view

of how humans see colors. Basical-

ly, the ellipses in the MacAdam’s

Ellipse diagram show areas where

there is no discernible difference in

color according to test subjects. The

CIE 1976 Chromaticity Diagram im-

proved on these distortions but was

admittedly still not perfect.

MacAdam’s Ellipses

1800s 1931 1976

Our knowledge

of how our

cones work has

evolved.

CIE 1976 is better suited to human visual perception because it incor-

porates MacAdam’s Ellipses and more closely parallels how our cones

work, using a new paradigm called the Opponent Theory.

7776 MK350 Series Survival Handbook

Measuring Light

The MK350 Series are UPRtek’s

precision Spectroradiometers (i.e. light meters) includ-

ing the Advanced, Basic and Compact models. They

are differentiated by functionality, usage and size.

The Advanced model has a very wide range of features

and measurement capabilities, and can cover most

portable applications from basic measurements to spe-

cialty analysis, comparison and administration.

Both the Basic and Compact models provide the user

with a quick snapshot and basic measurement infor-

mation. The Compact model only has a small visual

screen but is conveniently pocket-sized. Both of these

products were given a tremendous boost with the

ability to connect to the uSpectrum PC software and

the Smart Phone Apps. Additionally, the Compact

model was recently upgraded with a new feature called

Flicker sensor.

Advanced Basic Lite

MK350 Series - Things you should know

Advanced MK350S, Basic MK350N and Compact MK350D

MK350 Series - Things you should know

Advanced MK350S

Basic MK350N

Compact MK350D

7978 MK350 Series Survival Handbook

MK350 Series

Watch a Video

The MK350 User Manuals will explain most of the

features and functions, which we will skip here (you

should read the User Manuals at some point). In this

section we’ll look at some of the special terms and

functionality that were not covered in depth in the

User Manual.

We’ve already talked about how a

meter device can capture a white

light and derive an x,y coordinate

for our chromaticity diagram.

In that discussion we used a prism

to separate the colors in white

light - but actually, in our MK350

devices, we have what is called a

diffraction grating that does the

same thing but more efciently

and effectively.

http://www.youtube.com/watch?v=pxC6F7bK8CU

Diffraction Grating

Prism

The simplied explanation is that

light is received through a small slit

which transmits and reects off lens-

es and the diffraction grating to -

nally reach the CMOS sensor which

is the device that actually senses the

dispersed light waves to be recorded

as wavelength and intensity data.

Cmglee - CC-BY-SA-3.0

MPastermak - CC-BY-SA-3.0

Specialty Terms

Diraction Grating

Diraction Grating

Light Source

Lens

Diraction Grating

CMOS Sensor

Slit

8180 MK350 Series Survival Handbook

MK350 Series

Another term you will run into is Cosine Correction. It is associated with

measuring illuminance or how much light brightens a certain area - it is

measured in LUX which is lumens per sq. meter. A lumen is a unit of mea-

sure that represents an “amount” of visible light.

First, you must know that light coming in at an angle will inuence the

brightness or LUX. A light shining from directly above will shine bright-

er than a light coming in at an oblique angle. In fact there is a direct cor-

relation between the angle of the light and amount of brightness - this was

explained by Johann Heinrich Lambert in 1760.

Measuring light intensity on a at light meter lens is not so straight for-

ward, especially when trying to measure light coming in at angles and then

accurately recording the brightness according to the Lambert’s laws - you

need to make adjustments or innaccuracies will occur. These adjustment are

called Cosine Correction and there is a chart (next page), which is a guide

to measuring brightness according to Lambert’s laws.. The MK350 (as with

most light meters) uses a Diffuser or Cosine Diffuser that “diffuses” the light

to arrive at a more appropriate calculation of LUX. Diffusers are physically

apparant on certain meters where you can see a white opaque material just

under the lens. However, no diffuser is 100% accurate and you can only

attempt to arrive at ideal corrections for light arriving at angles.

Ideally, Cosine Correction for oblique (angular)

light should follow the graph shown below. For

example, a light hitting our surface at 60 degrees

should register radiant intensity in the meter at

around 50%. As the angle becomes less oblique,

the intensity should increase according the circular

orange line in the graph below. A Diffuser is in-

stalled in MK350 devices to get as close to the ideal

pattern (orange circle) as possible.

80%

60%

40%

20%

100%

Light coming in at 60

degrees should result

in about 50% of it’s

original intensity.

Cosine 60 degrees = .5

or 50%

Cosine is a mathematical function

used to calculate and specify the

characteristics (length & angles)

of triangles (Trigonometry). The

orange circle in the graph above

was described by Johann Hein-

rich Lambert in 1760 and is called

“Lambert’s Cosine Law”. Basically,

it shows how light intensity changes

as the angle of the light changes.

Diffuser

Cosine Correction

TELL ME MORE

8382 MK350 Series Survival Handbook

MK350 Series

Light Source

Lens

Diraction Grating

CMOS Sensor

Slit

Electrical charge residue

Dark Calibration is an optional operation in all of the MK350 devices. The devices will always

ask if you want to perform a Dark Calibration each time you turn on the device. While the device

is in operation, you can also, through the “Options” menu, manually execute a Dark Calibration.

What is Dark Calibration used for? Basically, an electrical residue or “charge” accumulates on

the CMOS sensor and may interfere with accurate measurements. This charge builds up when

the temperatures you are operating in changes signicantly. The other situation is when you

move from lighter to darker environments or vice versa. Also, it is a good time to perform a Dark

Calibration anytime you are experiencing some anomalies in measurements. The MK350 devices

always ask if you want to perform a Dark Calibration when powering on your device because it is

just good practice to do so.

Dark Calibration

8584 MK350 Series Survival Handbook

MK350 Series

The detail in Spectral peaks for uorescent

lights may be too ne and could be smoothed

out by the Mk350.

For all intents and purposes, yes it can. However, there is

one aspect of Fluorescent Lights to be aware of. The color

spectrum is NOT a conveniently xed set of individual

wavelengths to measure, but a continuum of wavelengths

(like a rainbow). It’s impossible and impractical for any

light meter to carve up the spectrum into innitely small

wavelengths. So, it carves up the spectrum into sections

and then does some averaging to come up with a continu-

um color spectrum to display on the screen.

However, everything within the width of the carved sec-

tion is averaged and details within are smoothed out. For

LEDs and Incandescents, it isn’t a problem - but for Fluo-

rescent Lights, the individual peaks are so thin, the device

may not have the resolution to catch all the details within.

This is the case with the MK350 and Fluorescent Lights.

The resolution of the MK350 is 12nm - this means that

2 or more peaks that fall within 12nm will be smoothed

out. Fluorescent Lights have peaks that can fall well

within 12nm - and so they are all smoothed. So what we

can determine from the MK350 and Fluorescent Light is a

general wavelength spectrum shape only.

To the right is the uSpectrum software, which can display

the half-bandwidth (Show Peak On). The half-bandwidth

is calculated by taking the λp (peak wave height)

and di-

viding it by 2 - next, at that 1/2 height, draw a vertical line

across the wave

- the thickness of the wavelength at that

height is called the half-bandwidth

. The half-bandwidth

for the peak shown in the diagram (right) is 14nm. How-

ever, since this is a Fluorescent Light, there may be several

sub-peaks within the 14 nm peak that were smoothed out.

Can the MK350 measure Fluorescent?

Measuring Fluorescent Light with MK350

half-bandwidth

Arne Nordmann (norro) - GDFL- CC-BY-SA-3.0 Wikimedia Commons

Half Bandwidth

On the uSpectrum screen, you have to turn “Show Peak”

- after a capture, the half-bandwidth will display in

the upper left corner

. Any detail within 12 nm sections

of the span will be smoothed out (averaged).

Half bandwidth is used by LED manufacturers to mea-

sure the thickness of the peaks, to try to measure color

consistency - too fat or too slim will obviously alter color

quality.

Sun Ladder - CC-BY-SA 3.0 - Wikimedia Commons

Half Bandwidth

8786 MK350 Series Survival Handbook

MK350 Series

Previously, we discussed Black Body Radiators - basically, it is an object that heats up

and emits different wavelengths of light (color) as the temperature rises - these colors are

identied as Color Temperatures in Kelvin and are indicated on the Chromaticity Diagram

below as the black curved line, otherwise known as the Planckian Locus. Generally, the

Color Temperature (CT) for light bulbs tells designers whether the light emits a warm feel-

ing (inclined to reds) or cool feeling (inclined to blues).

Warm Feeling 2500K Cool Feeling 5600K

Why is it called Planckian Locus? Because Mr. Planck

came up with the mathematical equation (and constant) that explains the rela-

tionship between temperature and color (for incandescent sources of light like the

Sun or a Candle).

10000K

6000K

4000K

3000K

1500K

2000K

2500K

5000K

Planckian Locus

Max Plank 1858-1947

Paulschou at en.wikipedia- CC-BY-SA-3.0

Planckian Locus

8988 MK350 Series Survival Handbook

MK350 Series

This section lists the various unit mea-

surements and the page number where an

explanation can be found or a direct expla-

nation.

Rundown of Unit Measurements

Unit Msr. MK350S MK350N MK350D Explanaon

CRI (Ra)

P P P

Lighng Store Display p130

CCT

P P P

Lighng Designers p107

LUX

P P P

Cosine Correcon p82, Lighng Designers p100

λp

P P P

Tallest peak in the Color Spectrum

I-Time

P P

Integraon me (like exposure me)

λd

Tesng and Calibrang LED-based screens and monitors p126

Purity

Tesng and Calibrang LED-based screens and monitors p126

R1-R8

P P

Lighng Store Display p 130

P P

Lighng Store Display p 130

R10-R15

P P

Lighng Store Display p 130

P P P

Part of the Chromacity Explanaon p62

P P P

Part of the Chromacity Explanaon p62

u’

P P P

Similar to x coordinate but for CIE 1976 (p77)

v’

P P P

Similar to y coordinate but for CIE 1976 (p77)

Duv

Lighng Designers p108

∆x

Lighng Designers p108

∆y

Lighng Designers p108

∆u’

Lighng Designers p108

∆v’

Lighng Designers p108

PPF

Explained on p99

PPF-UV

Explained on p99

PPF-B

Explained on p99

PPF-G

Explained on p99

PPF-R

Explained on p99

PPF-NIR

Explained on p99

P P

Foot Candle - Similar to LUX but is used mostly in the US. 1fc= 10.764 lux

Flicker %

Measuring Flicker p116

λp Value

(Lamdba PV)

Irradiance Intensity - “Lambda P” (λp) tells you the wavelength that has

the tallest Peak, “λp Value” tells you how tall that peak is in terms of

intensity.

a - Requires uSpectrum Soware

9190 MK350 Series Survival Handbook

MK350 Series

These are the different color spectrums that you should get to know ...

Recognizing dierent wavelength spectra

Fluorescent Light LED Light Incandescent Light

The important LED character-

istic to understand is that there

are two peaks. The rst peak

represents the bluish light from

the semiconductor. The green-

yellow-red peak indicates the

colors emanating from the yel-

low phosphor layer.

Fluorescent Lights have this

distinctive jagged continuum.

Notice the small amount of UV

radiation (under 400nm) - it’s

presumably from the UV radia-

tion emanating from the Mercu-

ry vapor (CONFIRM).

This is from an Incandescent

bulb. This continuum of color

wavelengths is indicative of a

Black Body radiator. Notice

how it leans more towards the

red colors - that is what makes

incandescent lights feel “warm-

er”. As you increase the tem-

perature of a Black Body Ra-

diator, the color should change

from reds to more blues (see

Sun Light on next page).

Recognizing Dierent Wavelength Spectra

Sun Light

Can you guess where this was

captured? Hint - notice the

jagged peaks, but also notice

the distinctive blue peak and

green-yellow-orange peaks.

Taken between LED and Fluorescent Lights.

Sunlight is the gold standard for

light. Notice that it has the most

even continuum of colors, which

means it renders all colors very

vividly. Also notice the relative-

ly high amounts of UV radiation

(< 400 nm) which is harmful to

the eyes and skin.

9392 MK350 Series Survival Handbook

MK350 Series

MK350

Wikipedia Creative Commons Attribution-Share Alike 3.0 Unported - no author

Applications

App

Applications

Wikipedia Creative Commons Attribution-Share Alike 2.0 Geeric - Tony Hisgett

9594 MK350 Series Survival Handbook

Applicaons

Watch a Video

Indoor Agriculture has been in-

creasingly gaining interest as a

means for plant-assisted growth

using articial light. This has

ramications for supplemental

food production during winter

months, especially in regions

with short-days and reduced

sunlight. This technology also

has the commercial potential for

Light Reactions

Light

ornamental plants as well and even perhaps

for growing plants 24 hours / day.

Plant assisted growth using articial

light uses wavelengths described as PAR

(photosynthetically active radiation). It

is measured in PPF (Photosynthetic Photo

Flux), which is the amount of light in the 400-

700 nm range that falls on a square meter in 1

second: µmol m-2 s-1 (micromoles of photons

per meter squared per second).

Photosynthesis

Electrons are the key

By Kristian Peters -- Fabelfroh, GNU Free Documentation,

Creative Commons Attribution-Share Alike 3.0 Unported

Plants use Sunlight, Carbon Dioxide and Water to

make sugars used to fuel the plant’s activities (e.g.

growth, germination) - this is called Photosynthe-

sis. This process can be simplied into 2 steps -

Light Reactions and the Calvin Cycle (sometimes

called Photosystem II & Photosystem I).

Sugars are used for

growth, germination,

owering etc.

2 Calvin Cycle

Light

Sugar

ATP and NADPH are very

important energy stores (like

batteries) that can be used for

many processes. In fact, the

human body also uses ATP

and NADPH everywhere.

Light and

Agriculture

Light and Agriculture

http://www.youtube.com/watch?v=g78utcLQrJ4

Mike Jones - CC-BY-SA-3.0

9796

Applicaons

MK350 Series Survival Handbook

Human VisionPAR PAR

Plants photosynthesize at wider

range of wavelengths than what

we can see, mostly at the red and

blue ends of the color spectrum

and less in the greens. However,

not all plants synthesize in the

same way - different plants need

Why are most

plants green?

PAR sensors are also used out-

doors for agriculture or foresta-

tion to measure the amount and

quality of sunlight reaching veg-

etation, which could be affected

by cloud cover, forest canopy

cover, building shade or pollu-

tion.

PPF (full spectrum 400~700 nm)

PPF-R (Red 600-699 nm)

PPF-G (Green 500~599)

PPF-B (Blue 400-499)

PPF-NIR (near infra red 700~780)

PPF-UV (ultraviolet 380~400)

Chlorophyll a -430 nm and 664 nm;

Chlorophyll b - 460 nm and 647 nm;

Chlorophyll c1 - 442 nm and 630 nm;

Chlorophyll c2 - 444 nm and 630 nm;

Chlorophyll d - 401 nm, 455 nm and 696 nm

different wavelengths of light and even the same plant will require

different wavelengths depending on its development phase.

Chloroplasts are a subunit within a plant cell and contain Chlorophyll

- different plants have different types of chlorophyll and thus respond

to different wavelengths of light. The MK350S can measure PPF at

different ranges of wavelengths to determine if certain plants are re-

ceiving the appropriate amounts of light at the right colors.

The Advanced MK350S can

measure PPF

(photosynthetic photo ux)

Chlorophyll Peak Sensitivities

Measuring PAR

PPF Values

By Kristian Peters -- Fabelfroh, GNU Free Documentation,

Creative Commons Attribution-Share Alike 3.0 Unported

Aushulz - GFDL - CC-BY-SA-3.0

Because the molecular structure is such that it reects green colors.

9998 MK350 Series Survival Handbook

Applicaons

Dialux is 3D software used

by Lighting Designers to help

plan luminaire lighting for

almost any situation includ-

ing building lighting, home

lighting, street lighting. The

designer receives an AutoCad

premises layout from a client,

which can be imported into

Dialux as a oor-plan - from

there, the designer can recon-

Luminaires

A Luminaire is sometimes called a Light

Fixture and is a complete lighting unit that

consists of one or more bulbs and every-

thing else needed for end-user installation

- encasement, sockets, connectors, reec-

tors, and power sources.

Lighting Designers

ialux

struct the entire client environment complete with colors, windows,

walls, ceilings, roof, doors and furniture. Finally, the designer is able

to select a set of simulation luminaires, which are ready to install

simulation light bulbs from vendors all around the world. In order

to do this, the vendor must have an IES le to download - these les

contain light specications about their lighting products. Finally, lu-

minaires are installed and light simulation can be evaluated. From

here designers check brightness or LUX, which is lumens per sq.

meter. A lumen is a unit of measure that represents an “amount” of

visible light. The Dialux software produces reports that show LUX

levels in every room, on oors, tables and walls.

Lighting Designers

Dialux

Bulb Selector

Lighting Vendor Selector

Furniture Selector

Tennen-Gas - CC-BY-SA-3.0

101100 MK350 Series Survival Handbook

Applicaons

102

Software simulations and reports are one thing,

but actual implementation and results are anoth-

er matter. Once all the real lighting has been in-

stalled, other than visual, there is no quantitative

way to show the client that your lighting instal-

lation meets original specications. This is im-

portant, because sometimes it’s necessary to meet

regulations for public spaces, such as libraries and

schools. The lighting designer uses the MK350 to

You can nd many guidelines on

the Internet from different organi-

zations, but the “word” is that most

of them are very similar. Some of

these organizations include:

show clients that, in fact, LUX levels on tables,

walls and workspaces do meet regulations.

Lighting regulations for public spaces is some-

times mandated and sometimes just guidelines,

but no matter, most developed countries are be-

ginning to pay attention to the importance of

proper, appropriate illumination and light color.

US - OSHA (Occupational Safety and Hazard Association)

UK - HSE (Health and Safety Executive)

EU - CEN (European Committee for Standardization)

When the Lighting Designer is using the MK350 to validate LUX for a library client, he/she positions the

device at just the height of the table, which is where you will normally be placing a book. The height is

important because even a short difference in distance of 33 cm can make a difference of 30-40 LUX.

Light Source

Table

Importance of mea-

suring LUX from the

right height.

Reading Level

typical areas of applicationIlluminance Level (lux)category

Minimum service illuminance in exterior circulation areas,

outdoor stores, stockyards

Exterior walkways and platforms

Boiler house

Transformer yards, furnace room etc.

Circulation areas in industry, stores and stock rooms.

Minmum service illuminance on the task

Medium bench & machine work, general process in chemical

and food industries, casual reading and filing activities.

Hangers, inspection, drawing offices, fine bench and machine

assembly, color work, critical drawing tasks.

Very fine bench and machine work, instrument & small

precision mechanism assembly; electronic components,

gauging & inspection o f small intricate p arts ( may be partly

provided by local task lighting)

Minutely detailed and precise work, e .g very small parts of

instruments, watch making, engraving.

General lighting for interiors

Additional localized lighting

for visually exacting tasks

General Lighting for rooms

and areas not frequently

used and /or used for

casual or simple v isual

tasks

3000

100

150

200

300

450

1500

103102 MK350 Series Survival Handbook

Applicaons

Measuring LUX

Uniformity

LuxG view also allows a

lighting designer to gauge

the even-ness or uniformi-

ty of light, which is hard to

otherwise do with the dis-

traction of objects, colors

and textures.

Here are some other simple things

that you should know. There is “Illu-

minance” which was the light we just

measured with the library example -

it is measured in LUX. Then there is

“Luminance”, where you measure LUX

that is reected off the table surface.

Of course, Luminance also depends on

the surface material - a black table top

would show a lower LUX than a white

table top.

In measuring Illuminance, if you move

the light source farther from the table

top, the area of illumination naturally

increases - this increase is proportion-

al to the square of the distance. At the

same time the LUX also is reduced

proportionally (at “2d”, LUX is 1/4 of

what it is at “d”, at “3d” LUX is 1/9 of

what it is at “d”).

As you move farther away laterally

from the center of the light, the LUX

also diminishes in proportion to dis-

tance. These are some of the items to

consider in lighting design.

Objective Luminance

Lighting Designers use

the MK350 LuxG view

to get a more objective

view of where luminance

is and where adjustments

are necessary. The red

areas indicate intense

light which, in this LuxG

image, falls mostly on the

oor and background.

area

4 x area

9 x area

Distance

2 x Distance

3 x Distance

16m

32m

MK350 (500lux)

MK350 (250lux)

Working plane

Measuring the LUMINANCE

of the light reflected off of the

working plane

Measuring the

ILLUMINANCE directly

from the light at the level

of the working plane

105104 MK350 Series Survival Handbook

Applicaons

Cool vs Warm - Color Temperature

Lighting designers are telling us that most of their clients are not familiar with the Color

Temperature. However, they do understand the concepts of warm and cool environments.

With Incandescent lights, the color temperature is used by designers to determine ranges

for Warm, Neutral and Cool as shown below.

Remember that color temperature is based on a theoretical model called a Black Body Radiator

(heat to make light) and the Sun and Incandescent Lights are fairly accurate representations of that

because they use heat to emit light. However, as we know, LED and Fluorescent lights are based

on semiconductors and mercury/phosphors respectively, so a Black Body Color Temperature real-

ly makes little sense.

However, a Correlated Color Temperature was devised to estimate a color temperature for LEDs

and Fluorescents. However, this correlation can only give a broad range estimate. Remember that

the Planckian locus is the theoretical Black Body Color Temperatures on our Chromaticity Dia-

gram. The slash marks acrros this locus (shown below) indicate the Correlated Color Temperature

ranges for Fluorescents and LEDs. In other words, an LED spec’ed for a CCT of 4000 could be

a yellow-green to yellow-blue-orange or anything in between. Therefore, the CCT can be ambigu-

ous for estimating the warmth or coolness of light for a designer.

Cool vs Warm - Color Temperature

Correlated Color Temperature

Warm Light

3300K or below

Neutral Light

Around 3300K to 5300K

Cool Light

5300K or above

107106 MK350 Series Survival Handbook

Applicaons

∆v

∆u

Duv

For CFLs and LEDs, there are other unit measures that the MK350S provides to help the

designer estimate “warmth” or “coolness”. Let’s say your light falls on the point marked

with a red dot (below) - rst of all, the closer the red dot is to the Planck’s locus (blue dot),

the more true the CCT is for determining the “warmth/cooling” feel of the light. This dif-

ference is called the Duv (or Delta uv) for CIE 1976 diagram. More specically you can

get the Delta u (∆u) and Delta v (∆v).

That’s why we have Duv ∆u ∆v ∆y ∆x

Duv ∆u ∆v ∆y ∆x

∆v

∆u

Duv

So how does this help you determine real “coolness (blue)” or “warmth” (red)? It depends

on which side of the Planckian locus you are on, and the positive and negative values of

∆u and ∆v give you this indication. In general, a positive ∆u and negative ∆v leans more

towards the warm colors, and a negative ∆u and positive ∆v pushes the color towards the

cooler colors.

∆v

∆u

Duv

∆u+

∆v-

∆u-

∆v+

warmer

cooler

109108 MK350 Series Survival Handbook

Applicaons

Paulschou at en.wikipedia- CC-BY-SA-3.0

Why not just look at the coordinates on the Chromaticity Diagram? - you can quickly see

where the colors are inclined to (warm or cool) - so you don’t really need ∆u and ∆v right?

Why not just look at the Chroma Diagram?

For a lighting designer, it may be enough to look at the Chromaticity Diagram. However, there are

advantages to working with numbers like ∆u and ∆v, particularly when you are working with lots

of data. With a list of ∆u and ∆v values, you can observe trends and deviations much more clearly

than you can by looking at a diagram. Furthermore you can take these numbers and calculate useful

statistical data, such as averages, means, and standard deviations.

Strength in Numbers

From data window of MK350 uSpectrum PC Software

∆y

∆x

∆y

∆x

∆x+

∆y-

∆x-

∆y+

warmer

cooler

∆y

∆x

∆y

∆x

∆x+

∆y-

∆x-

∆y+

warmer

cooler

The CIE 1931 also has delta values but they are in terms of delta x and y (∆x and ∆y)

λd

x,y

Still another way of determining “Cool”

or “Warm” is by running a line from the

white point (.33, .33) through your x,y

coordinate - where it hits the outer contour

is where the dominant wavelength (λd)

is and from that wavelength you can get

a sense of “cool or warm”. The MK350S

can display λd, without all of the fuss of

guring it out yourself.

111110 MK350 Series Survival Handbook

Applicaons

UV light or more accurately UV

radiation is harmful to the eyes

and skin. There many products

that offer UV Protection includ-

ing sunglasses, windows, and

sunscreen. The danger in sun

glasses is that if they are not

properly UV protected, your

eyes will open wider because the

intensity of the sun is mitigated

by the colored glass - however,

MK350 pointed at Sun

through Sunglasses

Note:

The range of UV Light is actually 10 nm to 400 nm,

but the MK350 only can measure down to 380 nm

- and so it only measures only the very top end of

UV radiation. Suntan lotion protects against harmful

UVB radiation whose wavelengths are 280 to 315,

which are too low for the MK350 to detect. All this

is to say MK350 cannot speak to UV protection de-

vices under 380 nm.

This image comes from the English Wikipedia

(Original author : Philip Ronan) -

GNu Free Documentation license Creative

Commons Attribution-Share Alike 3.0 Unported

at the same time, it will allow more UV

light to enter your eyes, without protect-

ing your eyes.

You can use the MK350 devices to

test sunglasses. From the two MK350

captures on the right, you can see the

dramatic reduction of UV region (380-

400) when using properly coated UV

protected Sunglasses. We should note

that UV protection is not only offered in

sun glasses but can be coated onto clear

glasses as well.

CFL UV light

See article below

http://ee.ret.gov.au/energy-efciency/lighting/incan-

descent-light-bulbs-phase-out/health-questions/mini-

mising-uv-light-exposure-articial-lighting

If you remember, Fluorescent Lights use UV radiation

to excite the phosphor coating inside the tube. Most

of the harmful UV light is absorbed by the phosphor

(UVC), but a small amount of UV light in the higher

UV region can be seen (UVA 380-400) by the MK350.

Measuring UV

light (radiation)

Light Health and

Safety

Light Health and Safety

Measuring UV Light

113112 MK350 Series Survival Handbook

Applicaons

Much has been discussed about

harmful “Blue Light”, which

refers to the visible blue region

from 400nm - 450nm (shorter

wavelength region of blue). It

is also referred to HEV (Harm-

ful Energy Visible) light and is

under suspicion of causing cell

damage in the retina and Age-re-

lated Macular Degeneration

(AMD). Also, post-cataract sur-

gery patients are more exposed

to HEV since part of the lens,

which yellows with age, is re-

moved and can no longer effec-

tively absorb the HEV blue light

(yellow is blue’s complement).

Measuring

Harmful

Blue

Light

The image below was taken with MK350S using the uSpectrum PC

software. MK350 shows a signicant reduction in HEV intensity

simply by turning down the blue color tones in the monitor’s color

adjustment panel. The monitor may appear distractingly yellowish at

rst, but your eyes will quickly get accustomed to it.

Blue Light ltering products include

Sunglasses that block out some of the

HEV light. There is a computer mon-

itor screen lter and even a low blue-

light monitor.

400 nm

Blue Light

450 nm 500 nm

Visible Light

500 nm 600 nm 700 nm

HEV Induced

Retina Damage

and cell Death

Exposure to HEV at night is

also mentioned in suppressing

Melatonin suppression (sleep

hormone) causing sleep disor-

ders by disrupting our circadi-

an (24 hr) rhythms. Anything

that is designed around LEDs,

TVs, Computer Monitors, Light

Bulbs all have the potential of

exposing you to HEV light. The

MK350 can easily reveal HEV

on the color spectrum.

http://www.visionmonday.com/

business/labs/article/protect-

ing-eyes-from-bad-blue-light-

vm-090913

LED monitors,

turn down the blue

Measuring Harmful Blue Light

http://www.youtube.com/watch?v=B8JrVESRcJk

115114 MK350 Series Survival Handbook

Applicaons

Flicker is the problem certain

lights have, exhibiting a subtle

pulsating or strobing effect, most

of the time barely noticeable by

the human eye - however, more

organizations are paying atten-

tion to icker because it is being

implicated in triggering a host

of health related issues such as

epilepsy attacks, migraines,

fatigue, reduced visual task

performance, distraction and

visual impairment.

The source of this problem is

the power current, particularly a

conict with the mains (from the

http://apps1.eere.energy.gov/buildings/publications/pd

fs/ssl/poplawski_dimming_lightfair2012.pdf

Dimmer

(these waves are NOT light color waves, but light intensity waves)

Measuring

Flicker

outlet) and the power supply (of

the light). Dimmers also induce

or increase icker. All lights

running on AC power have this

problem to a certain degree -

Fluorescent lights had long been

most criticized for high icker

before more recent advances .

Now LEDs are also beginning

to exhibit the same symptoms.

LEDs further complicate the is-

sue with their changing power

needs that come with tempera-

ture uctuations.

LEDs should be equipped with

what is called an LED driver -

it sits between the power supply

of the light and the light itself.

It’s main function is to regulate

or maintain a constant voltage to

the LED - a well designed driv-

er will adequately mitigate the

problems of icker. If an LED

is equipped with components for

other types of lights (e.g. trans-

formers), this will also cause

icker problems.

The MK350D is able to accu-

rately measure icker percent-

age from 1~100%. 0% is a pure

uninterrupted continuum of light

(no icker). 100% is when there

are complete breaks or 0 light

anytime in the wave.

Calculating

Percentage of Flicker

Measuring Flicker

Busch-Jaeger - CC-BY-SA-3.0

MK350D

117116 MK350 Series Survival Handbook

Applicaons

Power Supply

Driver

Mains

A good LED driver adequately

regulates power uctuations and manages

LED power needs, reducing icker.

State and Light Energy agencies are

already beginning to address this

serious problem with draft regula-

tions in progress (as of this writing

2/2014). The Russian government,

after reviewing exhaustive studies,

has implemented a ban on LED de-

vices with high icker rates.

Organizations such as Energy Star,

IEC, IEEE, EPA are all considering

Flicker standards at the time of this

writing (02/2014).

119118 MK350 Series Survival Handbook

Applicaons

Lighting

Road&Trac

Blue Shift

Yellow Shift

Heat Sink

Conversely, LED street

lamps and trafc lights

have a heat problem in the

Winter too. But it is the

lack of heat that is the issue

- LEDs give off heat but

much less heat than both

Incandescents and Fluo-

rescents - and this leads to

snow and ice build-up on

street lights.

Measuring

LED Degradation

Yes it’s true that LEDs can last up to 50,000 hours

and this means over 11 years of night time service

from LED street lamps. However, total lifetime

and useful lifetime are two completely different

things for LED lights. LED light quality inherent-

ly degrades in color and luminescence over time

and when its “useful life” as a street light is over,

there can be no compromise - they

must be replaced. The challenge is

how to monitor and maintain those

LED street lights, especially if

they are located in rural, even des-

olate highway areas. This is where

the MK350 devices are especially

important in practicality and con-

venience. Not only are they very

portable, these devices can auto

capture and log data over time,

which could be very convenient

for equi-spaced street lighting.

LED degradation is due to heat that passes through

the LED, and we know that heat can adversely af-

fect materials (e.g. incandescent laments). When

LED light quality degrades, you can assess where

the problem lies by looking at the color spec-

trum - most LEDs have a Blue peak and a Yellow

peak - the Blue is due to the light emitted from

the semiconductor - the yellow is the light emit-

ted from the Fluorescent lm (together they make

a white light). When there is degradation, what we

see in these spectrums are a blue-shift, where the

blue peak moves to the right toward the red - it is

a probable indication that the semiconductor ma-

terial is changing. It was also mentioned that the

yellow Fluorescent can also de-

grade, shifting downwards in the

spectrum (losing intensity).

This degradation is also a very

serious concern for LED trafc

lights where color is tantamount

to driver safety. Another issue is

weather - high temperature cli-

mates can also exacerbate degra-

dation. Yet another issue is that,

as difcult as it is to predict LED

color, it is as difcult to predict LED degradation.

These are all reasons that a portable LED light me-

ter like the MK350 devices for eld observations

are indispensable tools.

A few ways to alleviate heat related degradation is-

sues is to make sure you obtain good materials for

your semiconductor dies and also implement well

designed heat sinks to dissipate heat efciently.

A Wintery LED Issue

In this case, heating circuitry must

be built into the luminaires to sup-

plement heat to melt snow and ice.

In certain regions of the world, there

are very wide swings in hot-cold

temperatures and both heat dissipa-

tion and heating circuitry must be

built into the LED street light/trafc

light luminaire.

Measuring LED Degradation

Lighting Road & Trac

Tiverton UK - CC-BY-SA-2.0 Wikimedia Com-

mons

CmitryG - CC-BY-SA-3.0

- Wikimedia Commons

121120 MK350 Series Survival Handbook

Applicaons

In most developed countries,

it is critical to maintain proper

color quality for trafc lights .

Trafc lights using LEDs must

be carefully monitored as grad-

ual shifts in color over time

could result in signicant issues

in color perception as daylight

changes (due to time-of-day, )

cloud cover and air pollution.

It is important in pharmaceuti-

cal environments to make sure

high LED CRI (color rendering)

can render pill, tablet and label

colors appropriately to reduce

mishandling and problems in

pill identication. For the same

reason, it is important for senior

and elderly homes to account

for good CRI lighting. In oth-

er areas of a hospital, LEDs are

preferred because of long-life

- changing bulbs frequently re-

sults in loosening of dust from

the ceilings.

As LED technology has evolved

with more reliable CRI, CCT

and LUX specications, there

has been an increase in LED

surgical lighting as a cost sav-

ing, low-maintenance option to

Halogen based lights. In addi-

tion, the very low heat generat-

ed from LED lighting reduces

tissue necrosis. However, when

490

480

470

500

510

520

530

540

560

580

590

600

610

620

550

Measuring

Traffic Lights

In the US, the ITE (Institute of Trafc En-

gineers) sets strict guidelines and regula-

tions for color compliance.

Below is a sample Color Space with Bin

markings for trafc light color guidelines.

The MK350S has Bin Rating tools to help

assist these organizations in procuring ap-

propriate colored lighting.

Measuring Light in Hospitals

Surgical Lights

Measuring Trac Lights

Measuring Light in Hospitals

Surgical Lights

Wikipedia Creative Commons Attribution-Share Alike 3.0 Unported - no author Wikimedia Commons

manufacturing or purchasing

surgical LED lights, it is im-

portant to check CRI values, as

it will determine proper color

rendering for intricately visual

procedures.

123122 MK350 Series Survival Handbook

Applicaons

More recent Jumbo Screen / Jumbo

Tron wall-sized monitors are turning

to LED based display. These screens

are made up of groups of Red Blue

Green LED bulbs in the thousands.

Each group makes up a pixel of in-

formation like on a TV.

Replacement LED bulbs must match

the old LEDs to ensure proper color

and intensity match with the remain-

ing LEDs and this can all be easily

done with the MK350 device.

Otherwise, over time, the images on

the screen will begin to show anom-

alies in color. On another note, you

can use the MK350 to monitor deg-

radation of LEDs as well, because

this will also affect picture quality.

It then uses Color Mixing strategies to vary each group of

pixels to achieve the right colors in the right areas of the

screen. When these LEDs begin to degrade or when they

fail, they must be replaced. However, with the unpredictabil-

ity in LED light color, it is necessary to pay attention to the

light quality of the replacement bulb and an MK350 device is

a convenient device to do to just that.

Replacing LEDs in Jumbo Screen

124

LED Pixel Modules

Replacing LEDs in Jumbo Screens

125124 MK350 Series Survival Handbook

Applicaons

Any LED based TV or Monitor manufactur-

er can use a light meter to test screen colors.

You can even use Illustrator or Windows

Paint to ll an area with a primary color and

nd the dominant wavelength by displaying

λd on the Basic List.

You can use the MK350 to test the color

range of any LED based monitor. As you

know, the CIE 1931 chromaticity diagram

represents all the colors that we can see.

However, an LED monitor is only capable of

displaying only a subset of those colors. One

monitor brand might be able to display a larg-

er portion of the area. How do you check?

First establish where the Red, Blue and Green

points are for your monitor. Show a pure red

color on the monitor (Windows Paint) and

take your MK350 and hold it up to the screen

and take a reading with the Basic List show-

ing the dominant wavelength (λd). If you

draw a line from the white point (.33, .33),

and extend it to the furthest contour point,

it will be λd. This should tell you how true

your reds are on your monitor. (Note: your

monitor should be adjusted to Normal color

tones)

λd

Second, do the same for Green and Blue and

check their λd values. Then draw a line be-

tween the three points. The area within this

triangle are all the colors that this monitor

is capable of displaying - as you see there is

alot of visible color that it will not be able to

show.

λd and Purity

Testing and Calibrating LED Based Screens

and Monitors.

Testing and Calibrating LED Based screens and Monitors.

127126 MK350 Series Survival Handbook

Applicaons

Now, let’s look at another measure-

ment. It’s called “Purity”. Purity is a

percentage that is:

s/s+t = Purity

Purity tells us how close your color

is to the outer edge which represents

our pure colors.

λd

Now, let’s say that the purity of the

red color on another monitor is larger.

What this is telling us is that the RGB

triangle will be larger and thus, we

are able to see more of our visible

colors.

λd

If the Purities for the greens and

blues are also larger, our triangle

would be larger and the monitor

would be able to display even more

visible colors than the other monitor.

All this is to say, the larger the purity,

the better.

λd

If you are testing a monitor or screen

device, it will probably be using a

specic Color Space. With most

monitors you will nd that they com-

ply with the sRGB color space. This

is indicated within the white triangle

(left). It means that an sRGB moni-

tor can only display colors within it’s

triangle borders, which also means

that there is alot of visible colors that

it cannot display. You can then use

your λd and Purity values to see how

well your monitor’s triangle ts with-

in the sRGB triangle.

Adobe RGB is another color space

that monitors and printers can use.

Notice it’s triangle is larger and thus

can display more colors than sRGB.

sRGB, AdobeRGB

Wikipedia Creative Commons Attribution-Share Alike 3.0 Mbearnstein37

Wikimedia Commons

129128 MK350 Series Survival Handbook

Applicaons

Watch a Video

CRI (color rendering index) or

the ability of a light to proper-

ly render colors, such as reds,

greens, and blues, is important

in store display design, especial-

ly when using LEDs and Flu-

orescents. The sun is the gold

standard for CRI because it has

a full, even spectrum of colors

and gives us the vivid colors that

our eyes are used to seeing - so

a CRI value of 100 represents

the Sun and any thing less is a

measure of how close it comes

to the Sun.

The CRI values are 15 color

ranges, R

-R

- each range tells

us how much of each color is

coming from the light source.

There is a general “CRI” value

itself and it averages R

-R

- but

if your “CRI” value is 100, it

could be misleading if your are

looking at red, as in fresh meat.

To measure the value of reds in

your light you should really look

at R

. As you see from the two

pictures (right) a higher R

value

renders the red meat more red.

http://www.youtube.com/watch?v=tfK_FF-4aDI

Which oranges

would you buy?

To really see startling differences in store

display and CRI, see the video below at

about the 25 minute 16 second mark.

Note that the Basic and

Compact versions do not

have the CRI bar chart but

can show the “CRI” value

(r1-r8).

Note that CRI for Incandescent lights are

most likely to show favorable CRI (over

90) because, like the Sun, it is a Black

Body Radiator and displays a similar

spectrum of colors.

Importance of

CRI

Lighting

Store Display

Lighting Store Display

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Lighting

Academics & Research

MK350 is being used at Universities and Colleges as an in-

dispensible teaching tool, for understanding Light, Color

and Physics. Understanding light physics is about complex

mathematical functions and computations and the MK350 al-

lows teachers to train and test students by comparing student

computations with MK350 results. Thesis projects also take

advantage of MK350 uSpectrum software and software devel-

oper’s kit (SDK) for research.

MK350’s ability to capture, re-

cord and compare data is one

of the great advantages for re-

searchers gathering information

for thesis projects. Wireless fa-

cilities and software developer

kits make the MK350 a versatile

option for assorted testing envi-

ronments.

uSpectrum PC software and SDK (Systems Developer’s Kit)

Lighting Academics & Research

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MK350 Series Survival Handbook

MK350 is also being researched as a viable tool

for measuring surface colors (as opposed to

only light source). This has many ramications

in the market for standardizing and validating

color matches for printed material, fabric color,

component color uniformity, logo color compli-

ance. This also has ramications for studying

Metamerism.

Current Research

Measuring Surface Colors

When comparing two color patch-

es under one light source, the col-

ors may match - but when you try

it with another light source, they

fail to match. This is an optical

phenomena called metamerism. A

more practical example is where

you pick out a shirt and pants in

a department store because they

have matching colors - but when

you wear it outside under daylight,

the colors do not match anymore.

The MK350 may be able to ana-

lyze this phenomena and come

to understand how light spectrum

and surface reectivity cause these

problems.

Under light source 1

Under light source 2

Measuring surface color varies

widely with the source light. Ac-

ademic Research is under way to

determine if using spectrums from

standard white baseline juxta-

posed againt a color patch can be

mathematically combined to come

up with a standardized color, in

spite of the type of light source.

Metamerism

Research - Measuring Surface Colors

The above color spectrum captured a white baseline swatch (blue line) and a red test swatch (yellow line)

under an LED light using a test lens tunnel accessory (see next page).

Information is courtesy of Professor MeiJun Lo of

the Shih Hsin University (Taiwan)

Source Light A

Source Light B

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MK350 Series Survival Handbook

University researchers have already con-

ducted experiments using the MK350 to

uncover optimal designs for LED heat

sinks to minimize LED light and color

degradation over time.

Heat Sink Design Research

University Professors and Lighting Design-

ers write books about lighting both from a

design perspective and teaching perspective.

The MK350 is a cost-effective, easy-to-use

alternative to otherwise expensive, bulky

equipment that must be borrowed or rented.

Publish or Perish

Performance of Light Emitting Diode on Surface Machined Heat Sink

S. Shanmugan*, D. Mutharasu, O. Zeng Yin

Nano Optoelectronics Research Laboratory, School of Physics, Universiti Sains Malaysia (USM),11800,

Minden, Pulau Penang, Malaysia

Measuring colors on a sur-

face with an MK350 device as

shown (right) will let too much

peripheral light in. Because the

MK350 performs Cosine Cor-

rection your results will show a

spectrum closer to the dominant

light source. Trying to block out

the peripheral light by pressing

the lens up against the surface

will block out all light and will

only produce results for black.

UPRtek is currently research-

ing accessory devices as shown

right to block out peripheral light

while capturing only the surface

area in front. However, even

with this procedure, you are still

at the mercy of the source light

colors.

Peripheral light obscures

surface measurements

Accessory lens tunnel

blocks peripheral light.

LED Heat Sink Research

Research Publishing

Being able to measure surface

colors will help companies

monitor their brand colors, es-

pecially in the outdoors, where

sunlight is apt to oxidize paints/

inks and fade colors over time.

Many companies are especial-

ly cognizant of displaying true

brand colors and will be quick

to replace them when color deg-

radation falls below standards.

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Manufacturing

Professionals

LED manufacturing professionals are

people working in the three basic types

of LED manufacturing companies.

The LED Chip Manufacturer produces

semiconductor chips that come on wafers.

This is an important process of mixing al-

loys and impurities (doping) to produce

the nal wafer product.

www.youtube.com/watch?v=AMgQ1-

HdElM (www.microchemicals.eu)

The nal process is done by LED Bulb

Manufacturers. This includes applying

the housing, power supply, driver and any

other remaining wiring and componentry

needed to nalize the bulb or luminaire for

delivery to the end customer.

www.youtube.com/watch?v=ltqO3O8MMws

(ChromaAutomation)

www.youtube.com/watch?v=SoCfcETd72Q

(Formetcolnc)

The LED Assembly Manufacturer re-

ceives wafers, and using mostly robotics,

apply the appropriate circuitry (wiring)

and cut the wafer into chips. These chips

are tested for color and light properties

(robotically) and at this point are classi-

ed and physically separated into bins.

Then chips from one bin are mounted on

a circuit board. Fluorescent lm is also

added. After further preparation, they are

cut into individual circuit boards.

LED Professionals

Wikipedia Creative Commons Attribution-Share Alike 3.0

Wikimedia Commons

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MK350 Series Survival Handbook

Even though the assembly lines

in all 3 types of LED manufac-

turing companies are equipped

with robotic facilities for mea-

suring light properties, there

remains many ancillary applica-

tions where the portable MK350

devices remain an indispensable

industry tool.

Research and Development in

all three types of companies

are using the MK350 in their

test labs. Experimentation is a

laborious, time consuming pro-

cess taken up by collecting data,

testing, comparing, and analyz-

ing. Though these companies

have sophisticated equipment

(e.g. integrating spheres), the

workow for this type of pre-

liminary research work is best

All LED Bulb Companies create deep channels in the LED

market through distributors, agents, wholesale and retail

stores, all of whom need to compare and evaluate LED

light and color quality as never before. Even end-users

such as factories, libraries, museums, department stores

will become more savvy about LEDs and agents must be

prepared to validate LED quality offsite with a reliable,

precision meter. These same meters are also proving in-

valuable at lighting exhibitions, allowing buyers to evalu-

ate while sellers validate.

Practicality vs. Precision

There are hundreds of thousands of LED components rolling off of as-

sembly lines every minute and it is impossible to provide 100% quali-

ty-control for every single item. However, at certain points in the SOP, it

is prudent to sample items periodically to ensure that processes upstream

are performing as expected. This type of spot checking is easily and read-

ily performed by the MK350. In addition, data can be easily logged for

purposes of reporting and evaluating defect rates.

served by the compact, portable

MK350. It is said that margin in

precision between a sphere and

an MK350 is far outweighed by

the immense practicality of the

MK350.

The MK350 works with the uS-

pectrum PC software and that

ultimately is the key to this type

of work, providing full screen

PC connectivity, with data log-

ging, multiple item compari-

son, sorting and annotation - in

addition, UPRtek provides dll

libraries allowing companies to

develop their own software to

match their own testing facilities

- some companies are even mak-

ing customized MK350 ttings

to semi-automate testing using

MK350 auto-logging facilities.

Quality Control

Research and Development

Lighting Exhibitions

Research and Development

Quality Control

Light Exhibitions

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The Judge

The big three manufacturing arms of the LED industry are not without

occasional disagreements. The MK350 series is often used to settle dif-

ferences in light quality between companies. In one case, an LED bulb

maker used the MK350 color spectrum to reveal a aw in the Blue peak,

showing abnormal double horns, settling a dispute between semiconduc-

tor company and the assembly company.

Blue Shift

Yellow Shift

Chris Potter - CC-BY-2.0-Generic

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MK350 Series Survival Handbook

r g b

380 0.0272 -0.0115 0.9843

385 0.0268 -0.0114 0.9846

390 0.0263 -0.0114 0.9851

395 0.0256 -0.0113 0.9857

400 0.0247 -0.0112 0.9865

405 0.0237 -0.0111 0.9874

410 0.0225 -0.0109 0.9884

415 0.0207 -0.0104 0.9897

420 0.0181 -0.0094 0.9913

425 0.0142 -0.0076 0.9934

430 0.0088 -0.0048 0.9960

435 0.0012 -0.0007 0.9995

440 -0.0084 0.0048 1.0036

445 -0.0213 0.0120 1.0093

450 -0.0390 0.0218 1.0172

As convenient as a model RGB seems

to be, alas, it’s not perfect - RGB CAN-

NOT reproduce all the colors we can

see. Draw a triangle from our 3 pure

colors of Red Blue and Green and you

can see this - the area within the triangle

are really all the colors RGB can simu-

late, which is obviously not all the col-

ors we can see. There is a large area in

the blue-green that humans can see but

are not contained in the triangle. Why?

This is because the RGB additive model

is not perfectly aligned with how we see

colors.

Red

Blue

Green

x,y

Appendix 1 - CIE 1931 In- depth

Appendix 1 - CIE 1931 in-depth

100%

R 700nm

G 546.1nm

B 435.8nm

To account for the inadequacies of RGB, the experimenters

added red light to the “test” color. If you plot the original

experimental data, you get the 2D graph below-left with

negative red values.

Troublesome negave values for the Red

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MK350 Series Survival Handbook

Mathemacally adjusted for negave Red values

The Color Matching Function chart data is then transformed further into what we call

“X”, “Y” and “Z” values (in capitals) - these values represent still another way in which

humans see color, but they are still, in essence, tristimulus values derived from the

original RGB human experiments. The transformation formula is shown below, using

integral calculus - here we also must introduce I(λ), which is the intensity (or SPD -

Spectral Power Distribution) of each of the wavelengths and λd represents the resolution

or slice of each wavelength taken from the continuum (spectrum). The formula sums all

the wavelength data into a single X, Y and Z data set.

So let’s go through the process again of calculating an x,y coordinate for a light source.

1) MK350 captures light and separates it into multiple wavelength data along with their intensities,

2) sends data through Color Matching Functions, 3) transforms that data into an XYZ point in 3D

space (mathematically), 4) normalizes to Unit Plane (mathematically , and 5) plots it to an x,y 2D

plane

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

1, 1, 0

1, 1, 1

1, 0, 1

0, 1, 0

0, 0, 0

0, 1, 0

1, 1, 0

1, 1, 1

1, 0, 1

0, 1, 0

0, 0, 0

0, 1, 0

1, 0, 0

0, 1, 0

0, 0, 0

0, 1, 0

x, y

Use Color Matching and SPD data

to transform to a single point

(represented by X, Y, Z in 3D space

below).

1 2

3 4

Mathemacally normalize to

Unit Plane (x+y+z=1). Import-

ant - the proporons of the 3

values have not changed so it

sll represents the same color.

Use the Unit Plane to make a 2D

x,y coordinate system, and plot

the x,y coordinates on the Color

Gamut explained in the earlier

sectons..

Capture light, disperse wavelengths, record SPDs

Send each wavelength data through

Color Matching Funcon

Test Color - 580 nm

100 %

0 %

100 %

R 700 nm

G 546.1 nm

B 435.8 nm

1,1,0

1, 1, 0

1, 1, 1

1, 0, 1

0, 1, 0

0, 0, 0

0, 1, 0

1, 1, 0

1, 1, 1

1, 0, 1

0, 1, 0

0, 0, 0

0, 1, 0

1, 0, 0

0, 1, 0

0, 0, 0

0, 1, 0

x, y

The smart people at CIE mathematically adjusted these negative values and came up

with a new graph or the Color Matching Functions shown below. Notice that the red

line that was below the axis (negative) now lies on top of it. Keep in mind that these

new functions are still originally based on the RGB experiments.

Note that there sll are some simplica-

ons for the sake of explanaon.

The CIE model capitalizes on this fact by dening Y

as luminance. Z is quasi-equal to blue stimulation,

or the S cone response, and X is a mix (a linear

combination) of cone response curves chosen to be

nonnegative.

www.wikipedia.org - CIE 1931

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Luo Meijun, Digital Color Management Science: Color Metrology, Publisher “Blue Ocean Cul-

ture”: Publication date 2011/04/29

Shanmugan S. D. Mutharasu and O. Zeng Yin Nano “Performance of Light Emitting Diode

on Surface Machined Heat Sink“ International Journal of Power Electronics and Drive System

(IJPEDS) Vol.2, No.4, December 2012, pp. 380~388

Kelly, Kevin M.A. B.Sc.(Eng) C.Eng. MCIBSE. MIEI and Kevin O’Connell M.A. B.Sc.(Eng)

C.Eng. MCIBSE. MIEI. Interior Lighting Design - A Student’s Guide

<http://eleceng.dit.ie/

kkelly/Lighting/Interior lighting design Students Guide.pdf>

Morton, J.L. Color Matters “Color & Design - Basic Color Theory” <http://www.colormatters.

com/>.

Blackwell, Craig MD Fellow American Academy of Opthalmology, diplomate American Board

of Opthalmology “Color Vision 4: Cones and the Opponent Process” Jan 2008 < http://www.

youtube.com/watch?v=V73k_0KuUJo>

Blackwell, Craig MD Fellow American Academy of Opthalmology, diplomate American Board

of Opthalmology “Color Vision 2: Color Matching ” Jan 2008 < http://www.youtube.com/

watch?v=82ItpxqPP4I>

HyperPhysics, Dept of Physics and Astronomy, Georgia State University “Light and Vision” <

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html>

Wikipedia “CIE 1931 color space” < http://en.wikipedia.org/wiki/CIE_1931>

Wikipedia “CIELUV” < http://en.wikipedia.org/wiki/CIELUV>

USAtoday “Why people still use incandescent bulbs” Dec 2013 <http://www.usatoday.com/sto-

ry/news/nation-now/2013/12/27/incandescent-light-bulbs-phaseout-leds/4217009/>

Design Recycle Inc. Comparison Chart LED Lights vs. Incandescent Light Bulbs vs. CFLs

<http://www.designrecycleinc.com/led comp chart.html>

Luxeon “How does an LED work Oct 17, 2013” <www.youtube.com/watch?v=BH9LI-

973H8w>

Bibliography

Cameron, Brad “Dr. Quantum- Double Slit Experiment” Sep 13, 2006 < http://www.youtube.com/

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Khanacademymedicine “Vision: Photo-receptor Distribution in the Fovea” 9/17/2014 < http://www.you-

tube.com/watch?v=UXIfzc1UH-g>

Learning Solutions “How does a spectrophotometer work?” Nov 4, 2011 < http://www.youtube.com/

watch?v=pxC6F7bK8CU>

BenQ “BenQ Eye-care Low Blue Light Monitor Demo Video” Oc 13, 2013 <http://www.youtube.com/

watch?v=B8JrVESRcJk>

British Broadcasting Corporation “BBC Design Rules 3rd Episode: Light” Aug 12, 2011 < http://www.

youtube.com/watch?v=tfK_FF-4aDI>

Bozeman Science “Photosynthesis” April 3rd, 2012 < http://www.youtube.com/watch?v=g78utcLQrJ4>

Formetco “The Making of a Formetco LED” Jan 13, 2012 <http://www.youtube.com/watch?v=SoCfcET-

d72Q>

ChromaAutomation “Chroma LED Bulb In-Line Assembly and Test Solutions” April 5, 2013 < http://

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MicroChemicals “Silicon Wafer Production” June 8, 2012 <www.youtube.com/watch?v=AMgQ1-

HdElM>

Vision Monday “Protecting Eyes Fromk ‘Bad’ Blue Light” Sept. 09, 2013 < http://www.visionmonday.

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Digi-Key Corporation “Characterizing and Minimizing LED Flicker in Lighting Applications” July, 17,

2012 <http://www.digikey.com/us/en/techzone/lighting/resources/articles/characterizing-and-minimiz-

ing-led-icker.html>

Hawk, J. Chris MD, Chair - Annual Meeting of the American Medical Association “The Role of Color

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UC Davis ChemWiki “Photo-receptor Excitation” <http://chemwiki.ucdavis.edu/Biological_Chemis-

try/Photo-receptors/Photoreceptor_Excitation>

PRWeb “LED Lighting Market Shares and Forecasts 2013-2019 in New Research Report at Reportsn-

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