03 "Colours of Objects and Colours of Light" (keynote), CSA Past President Dr David Briggs

This video is a recording of the keynote presentation by Past President Dr David Briggs for the CSA national conference "Colour Sense and Sensibility" held in Perth on October 12-15, 2023. The full text of the presentation is online at http://www.huevaluechroma.com/1118.php

The way we see the world has a remarkable layered quality that’s often overlooked. Our visual system instantly and seemingly effortlessly presents us with perceptions of the varying spectral reflectances of objects, and of the varying intensity and spectral composition of the light falling on those objects. We call these perceptions of spectral properties colours.

Because we tend to think mainly of colours of objects, the terms for colours of light (brightness, colourfulness and saturation) are much less widely understood terms for colours of objects (lightness and chroma), and even colour educators with decades of experience may present the differences between lightness and brightness, or between chroma, colourfulness and saturation, incorrectly, as being minor and unimportant at an introductory level. But as I emphasize in this talk, our perception of colours of objects is inextricably linked with our perception of colours of light.

Our perceptions of colours of objects are always accompanied by a superimposed perception of illumination, and this concept of perceptual layering of object and illumination colours is discussed using a series of animated examples. The presentation concludes with an observation of the ways groups with different backgrounds have quite different understandings of deceptively simple expressions like "the colour of an object" and "colour constancy".

Links mentioned in presentation

Briggs, 2023b. The Elements of Colour. Parts One and Two. Journal of the International Colour Association, Volume 33, Special Issue: Contributions of the Colour Literacy Team, editor Robert Hirschler:
https://aic-color.org/journal-issues

Commission Internationale de L’Eclairage (2020), CIE S 017:2020 ILV: International Lighting Vocabulary (2nd edition). Definitions available online as the e-ILV at https://cie.co.at/e-ilv.

Attributes of colours perceived as belonging to (A) objects and (B) light.
http://www.huevaluechroma.com/011.php

Alan Gilchrist’s ECVP 2014 Perception Lecture, Theoretical approaches to lightness and perception    • ECVP 2014 Perception Lecture: Theoret...  

https://www.verivide.com/it-looked-no...

Colour & Vision Research Laborarory, University College, London
http://www.cvrl.org

R. Beau Lotto
http://www.labofmisfits.com

Briggs, D. J. C., Colour Constancy Illusions and Painting. CSA 2018 conference: http://www.huevaluechroma.com/116.php

James Gurney, Banana demo, gouache, 2014 http://gurneyjourney.blogspot.com/201...