Light, Color and Improved Color Quality Possibilities with LED

Light, Color and Improved Color Quality Possibilities with LED Solutions Light – What is it made of? Light is made of waves (technically: electromagnetic waves of radiant energy) very small waves… Lights wavelength is measured in billionths of a meter, nanometer (nm) UV, Infrared (IR) heat, cell phone radio waves, X-rays are the same waves… just longer or shorter Visible Light is wavelengths between 380nm and 780nm Different Wavelengths = Different Colors

Light comes in different colors, spread across the rainbow of hues we call the visible spectrum.

Red waves are the longest, purple the shortest Different Wavelengths = Different Colors 4

Visible Light

Blue Green Red How Do Humans “See” Color

• The eye contains cones and rods - cones are color sensitive and used for high light level vision (photopic) , rods are for night vision (scotopic) • Three types of cones – long, medium and short .. Sensitive to red, green and blue areas of the visual spectrum • Cones are concentrated in high density in fovea, Rods are spread across a much larger area inside the eye How Do Humans “See” Color How Do Humans “See” Color

Sunlight

Twilight

Starlight Distribution of Rods and Cones Color Intensity Perception

White light consists of many colors mixed together

Natural White Light (such as sunlight) consists of a continuous spectrum of all colors

Power

Wavelength

Relative Human Eye Sensitivity The Human Eye Response Curve

555 nm Peak 1931 CIE Chromaticity Diagram How It Works 11 • Monochromatic (“high Saturation”) colors are on the outside edge of the diagram “The Spectral Locus” • All combinations of colors are on the inside, with white colors in the middle 1976 CIE Chromaticity Diagram 1931 CIE Chromaticity Diagram 12

Green

Red

Blue Blackbody Radiation

1931 CIE Chromaticity Diagram

Steel @ 1500K Noon time sun @ ~ 6000K Warm White Cool White

Tungsten @ 2700K B type star >11,000K Warm White Cool White Color Gamut Blue + Yellow Phosphor 15

Blue Peak

Yellow Phosphor CIE 1931 Color Space CIE 1931 Color Space Creating White Light

WHITE LIGHT

White Light for General Illumination Epitaxial Layer

Substrate

LIGHT EMITTING DIODE LIGHT EMITTING DIODE LED Package Phosphor

Blue LED

BlueGenerating + White Phosphor Light with LEDs Spectral Power Distribution

Daylight Incandescent

Phosphor Converted LEDs Spectral Power Distribution

Phosphor Converted LEDs

Metal Halide Fluorescent Phosphor Converted LEDs Precise Color Tuning Precise Color Tuning Two Source White Color Tuning

• Even with the two source method choices abound • Here is a system that starts and ends on the BBC

2700K

6500K

Tc(K) 6500 2700

Credit: Finelite, Inc. Two Source White Color Tuning

• Here is a system that starts above the Black Body Curve and ends below it

2700K

6500K

Tc(K) 6500 2700

Credit: Finelite, Inc. Comparing Spectral Power Distribution

Daylight Incan- descent

3000 K 3000 K Color Rendering Color Rendering Index (CRI)

– A quantitative measure of the ability of a light source to reproduce the colors of various objects faithfully in comparison with an ideal or natural light source – Ranges from 0 (poor) to 100 (excellent) Object Color Object Color

Spectrum

Vision Object Color Color Rendering Index

In general terms, CRI (Ra) is a measure of a light source's ability to show object colorsDaylight "realistically" or "naturally" compared to a familiar reference source, either incandescent light or daylight.

None of the 8 test colors used to calculate CRI are saturated. So, CRI is a poor measure for indicating how well a light source illuminates saturated colors.

Even with a high CRI (Ra), color rendering of saturated colors can be poor. CRI With Expanded Ra Example Color Rendering Index – R9

U.S. Department of Energy (DOE) Comments:

0 50 75 100

Poor Good Very good Excellent Color Like Nature Meant it to Be…

Color Contrast

Why is full spectrum color important?

This produce may appear reasonable under a broader color spectrum source.

What would you expect to happen under a Low Pressure Sodium lamp? Color Contrast

LPS LED What’s the Value of Exceptional Color Quality? Good CRI and Red Color Rendition is Important 43

For Illustrative Purposes Only Images: Courtesy GE Lighting Good CRI and Red Color Rendition is Important 44

For Illustrative Purposes Only Good CRI and Red Color Rendition is Important

Different Colors…

Should Look Different

Help People Look Their Best Tunable Fitting Room Lighting

Photo Credit; Lux Magazine High Color Rendering Can Enable Better Vision Without Requiring More Power

Published in March 2015 Collaborative paper between CLTC, University of British Columbia and the National Research Council of Canada.

Seeing is Believing Seeing is Believing LED Metal Halide

830W 3,070W Daylight at Night? Metal Halide LED 4000K ~65 CRI 5000K 90+ CRI R9 <0 R9 50+ 400W Metal Halide LED Solution

What now? Why color?

• Ask manufacturers for more info • Update basic color discrimination requirements CRI to: Rf and Rg • Why? • Pharmacy (h1 - red) • Branding • Diagnostic & NICU (Rfskin) • Labs • Color matching - textiles • Produce • Artwork • Vehicle details • Restoration • Salons & Hair Color 8 COLORS

CRI

99 TM-30 COLORS CRI

slide credit : Royer, Burkett, Esposito ies.org/ac 2018 CRI

slide credit : Royer, Burkett, Esposito ies.org/ac 2018 8 COLORS

CRI

99 TM-30 COLORS IES TM-30-18

slide credit : Royer, Burkett, Esposito ies.org/ac 2018 IES TM-30-18

slide credit : Royer, Burkett, Esposito ies.org/ac 2018 16 HUE SHIFTS 99 BINS COLORS

slide credit : Royer, Burkett, Esposito ies.org/ac 2018 IES TM-30-18

Why? • Better predictability of color quality • Customizable data What? • Average values (spec friendly) • Graphical representations of color • Color-specific values Reviewing a light source

slide credit : Royer, Burkett, Esposito ies.org/ac 2018 Reviewing a light source

slide credit : Royer, Burkett, Esposito ies.org/ac 2018

IES TM-30-18

Dept. of Dept. of Academia Defense Energy

slide credit : Royer, Burkett, Esposito 2018 IES TM-30-18

Same “Rf” Same “Rg” Different Rcs,h1 IES TM-30-18

Rfskin: Color 17 & Color 19 Q. What now? TM-30-18 • Investigate TM-30-18 with a team, or do a mockup • Ask manufacturers for more info • Update basic color discrimination requirements CRI to: Rf and Rg • Update complex color discrimination requirements Rf and Rg + Rcsh1 or Rfskin …custom combinations Color Impacts in Outdoor Lighting

• For visual detection, there is an improvement under white sources

• The application of color in the roadway environment appears to be related to color contrast. – Adding color provides an additional clue to the presence of objects and pedestrians in the roadway

• This can lead to an additional savings for the costs of outdoor lighting. Target Detection and Color Temperature

Note: CCT is horrible Metric for this Light Source and Detection

https://neea.org/docs/default-source/reports/seattle-led-adaptive-lighting- study.pdf?sfvrsn=4 San Jose – Detection distance vs watts per linear foot HIGH (100%) setting San Jose – Detection distance vs watts per linear foot LOW (50%) setting 87

Color Contrast Negative Spectral Impacts of Outdoor Lighting

• The spectrum of a light source can have negative effects in the outdoor environment – Health Impacts – Sky glow – Impact on Flora and Fauna • Bugs, Buds, Bears and Bass • As we move to full spectrum light sources for better color, we must manage how the spectrum is managed in the outdoor environment Health Effects

• In the move from the Amber HPS, there is a potential for a full spectrum light source to negatively impact our health. – The eye has a receptor that controls many of our circadian systems – Can impact health, sleep etc. – These effects are based on the amount and timing of the light experienced. • AMA has stated – Use 3000k • Reduces Sky Glow • Reduces impact in Humans • Reduces impact on Migratory Animals • Reduces impact on Sea Turtles – The results of this report are biased however and do not consider light dosage Potential Impact on Human Health

• Preliminary there may be an impact – Correlation but no causation • Roadway Lighting Levels are below thresholds – Research is on-going Sky Glow

• Sky Glow – Blue Light Scatters more than amber light • Rayleigh Scattering – Molecular Scattering – Molecule are about the same size as the wavelength for blue light – Blue Light Scatters more – Low angle blue content light is particularly bad • Mie Scattering – Aerosol Scattering – Particles are much bigger than wavelength – Not Spectrally Selective Relative Sky Glow 2.8

1.0

0.24

LPS HPS MH

From CORM 2008, Luginbuhl, Keith & Knox Impact on Soybean Growth Yield and Moisture

Maximum Values Illuminance Maximum, lx Horizontal 2.2 Vertical 1.8 Birds, Bass, Bears and Bees

• Lighting influences anything with eyes that are sensitive to visible light – Eg. Robin Song will start as much as 2 hours early in areas adjacent to Roadways (Kempenaers et al, 2010) Light Impact on Perch (Bruning et al)

• Melatonin is suppressed by red light – Opposite impact of humans Bridges We are changing the Ecology

• Crayfish hide and do not interact as significantly under roadway lighting • Bats now hunt under light fixtures • Slugs are on the rise • Salmon change their swimming depth Actinic Curves (Longcore et al) Proposal on how and when to select Spectral aspects of luminaires for outdoors

Lighting Type/Location Recommended CCT  Conventional & high mast poles on Interstates, 3000 K  High-speed primaries, and ramps 4000 K  Street lighting on low-speed urban streets 3000 K  Decorative post-top lights 3000 K  Overhead guide sign lighting 3000-4000 K  Rest area lighting (in overnight truck parking areas) 3000 K  Rest area lighting (no overnight truck parking) 4000 K  Environmental Sensitive Areas (Particularly Waterways) 3000 K or Lower

• Use Adaptive Lighting to Reduce Levels as much as possible when suitable 101

Renzo Shamey Simultaneous Contrast 102 103

http://www.purveslab.net/see-for-yourself/

Thank You for Your Kind Attention