The main purpose of this POST is to provide a link to Chapter 25 of my book “Painting with Light and Colour” to which I have given the title “chiaroscuro” (the light/dark dimension). But first a word to explain why this is situated in the part of the book on “Painting with Colour”, rather than the part on “Painting with Light”, as most people would expect.
Black is a colour
The reason for this anomaly follows from the facts of visual perception (a) that colour is made in the brain and (b) that the brain classifies shadows, shading and highlights as colour. This counterintuitive state of affairs is a consequence of the way the eye/brain combination separates out surface-reflection from body-colour. Thus, the neural algorithm responsible for this impressive feat, confounds the sudden changes in reflected-light that occur at the edges of regions of cast-shadows and highlights, with the sudden changes at the edges of regions of body-colour. For similar, though slightly more difficult to explain reasons, it also classifies gradations in the lightness profiles of surfaces as gradations in body-colour (for more on these reasons, see Chapter 9 of this volume and Chapter 14 of my book “What Scientists can Learn from Artists”).
Link to chapter 2
CHAPTER 25 – CHIAROSCURO
Two chiaroscuro masterpices


Chapters from “Painting with Light ” (Part 1 of this volume)
- INTRODUCTION to Book 1 of “Painting with Light”
- Chapter 1 : The dogmas
- Chapter 2 : Doubts
- Chapter 3 : The nature of painting
- Chapter 4: Renaissance ideas
- Chapter 5 : New Science on offer
- Chapter 6 : Early Modernist Painters
- Chapter 7 : The perception of surface
- Chapter 8 : Seurat and Painting with Light
- Chapter 9 : Seeing Light
- Chapter 10 : Illusory pictorial space and light
- Chapter 11 : Colour mixing – definitions and misconceptions
- Chapter 12: The colour circle: Misunderstandings
- Chapter 13 : Finding a maximum of colours
- Chapter 14 – Colour mixing made easy
- Chapter 15 – Colour mixing by layering
- Chapter 16 – Reviewing previous chapters (1)
- Chapter 17 – Reviewing previous chapters (2)
- Chapter 18 – “All you need to know about painting” – No 2
Thanks, Francis for posting this chapter which I found informative and practically relevant. This chapter and the next make a particularly useful pair. I very much enjoyed seeing Sarah’s drawings particularly the figurative house and garden-superbly evocative, especially the sense of sunlight, while avoiding becoming twee
Just re read your very interesting and refreshing article and totaly agree “no two parts of a painting should be of the same lightness”.
I first encountered this issue without realising it when aged 9. I painting of mine was held up as an example of an unusual solotion.
Later at Maidstone College of ArtI worked on this issue with charcoal, under the experienced eye of Christopher Ironside.
You Francis have provided the best clearest explanation of the issues that I have ever read or heard.
Congratulations, I raise my glass to you !