The mental images which we perceive are created in the brain, which has some fixed ideas about how to do that. They’re not the same as optical laws used in cameras and related devices.
An extraordinary optical illusion by Kokichi Sugihara.
We still associate brushmarks with sketchiness, speed of painting, spontaneity, bravura, and panache – and smooth paint surfaces, assembled from multiple layers and glazes, as being heartless mechanical essays in technique.
Lightness is key to the depiction of materials, textures, edges, and form. Illusions can confound the viewer, and it is vital to map the lightness of your motif to that of your painting.
What do we actually perceive of colour?
If we are to understand colour in painting, to comprehend how to apply pigment to depict what we see, we first need to understand our perception of colour.