An Experiential Conversation About Colour

●  What is colour?

●  Do we all see colour the same way?

●  Colour as illusion, ‘plastic’

●  Colour concepts in lighting: light and colour metrics, colour

discrimination, colour rendering,colour fidelity, gamut, TM30

●  Colour in action.

●  Application demands.

Yellow 597nm-577nm

Do we all see colour the same way?

colour association

colour preference

http://www.colourtest.ue-foundation.org/

Personality Luscher Colour Test

Choose the card colour you like best and then order the rest from most preferred to least preferred.

●  Blue: Contentment

Feeling of belonging, the inner connection and the relationship to one’s partner. "How I feel towards a person that is close to me" ●  Green: Self-respect

Inner control of willpower and the capacity to enjoy. "The way I want to be" ●  Red: Self confidence

Activity, drive and the reaction to challenges. "How I react to challenges" ●  Yellow: Development

Attitude of anticipation, attitude towards future development and towards new encounters. "What I expect for the future"

“In visual perception a color is almost never seen as it really is—as it physically is. This fact makes color the most relative medium in art. In order to use color

effectively it is necessary to recognize that color deceives continually. To this end, the beginning is not a study of color systems.” Josef Albers

metamerism

chromatic adaptation

How do we interpret the experience for lighting practice

Chromaticity: A measure of hue + saturation. Visually described as the apparent warmth or coolness of the light.

Measured in Kelvins (K) or as x,y values on a chromaticity diagram.

The Commonly Used Light & Colour Metrics

Digging deeper …

Chromaticity The CIE System of Colorimetry based upon the Trichromatic Nature of Human Vision CIE Color Space (1931 with revisions in 1960, 1964, 1976 and 1991)

The Commonly Used Light & Colour Metrics

CIE CRI 1960 UCS CIE CRI 1976 UCS

Colour Space Uniformity

Until now Colour Rendering has meant Colour Fidelity

colour rendering

Average Color Fidelity TM-30 Fidelity Index (Rf) On average, how similar are colors rendered by the test source to the same colors rendered by the reference illuminant? • Average length of arrows • Does not capture direction of shift Range is 0 to 100, where 100 is an exact match.

Average Gamut Area TM-30 Gamut Index (Rg) Approximation of average change in chroma. •Average area enclosed by samples •Does not capture how changes vary for different hues

99 samples plotted Coordinates averaged by 16 bins and compared to

reference illuminant

Vector Graphic shows how different hues are

rendered in different ways

Local Chroma Shift For a given range in hue angle, what is the average relative change in chroma. Values in percentages. Local Hue Shift For a given range in hue angle, what is the average relative change hue. Values in radians. Local Color Fidelity For a given range in hue angle, what is the average magnitude of change (3D). Values 0 –100.

Original image courtesy of Randy Burkett Lighting Design

Original image courtesy of Randy Burkett Lighting Design

Original image courtesy of Randy Burkett Lighting Design

Original image courtesy of Randy Burkett Lighting Design

Original image courtesy of Randy Burkett Lighting Design

Original image courtesy of Randy Burkett Lighting Design

how can colour enhance the experience?

Conclusions Not everyone views colour the same way Colour is subjective, viewers bring bias, evidence based science proving preference for higher saturation Colour is contextual, dependant upon surround, viewing angle, luminance, illuminance In many applications Colour Fidelity may not be as important as Chroma Shift and/or Hue Shift Traditional metrics of CRI and CCT alone leave a lot of information on the table TM-30 is simply a calculation procedure, not an RP or a predictive measure, not a ‘spec’ i.e., “This has a high TM-30” TM-30 considers the interplay of fidelity, chroma shift and hue shift distilling complex information into a digestible number or graphic TM-30 does not consider intensity, chromaticity, whiteness, scene composition or other contextual factors