John Locke's imaginary colours. A psychical or physiological study?
I have read some writing by Sacks but I am not sure if he has written on colours specifically. One thing I am aware of is that if I am feeling low, I feel that colours seem a bit wishy washy, whereas if I am feeling in great spirits, they seem to appear brighter.
The whole subject of seeing colour also falls into the area of ophthalmology. It seems to me that my mother sees colours differently since she had cataracts operated upon. To a large extent, visual perception of colour is dependent on the rods and cones and the retina, is part of the brain really. We know of people who are colour blind have severely altered sense of colour, but I wonder if we all see colours in exactly the same way generally, but this is probably an aspect which can be answered by neuroscientists.
However, the view of artists are probably relevant too. I remember it being so difficult to mix the exact shade of greens for certain leaves on trees. I think that there is plenty of khaki in the trees and I believe that camouflage, khaki designs was to enable soldiers to blend into the trees. Painting the sun in the sky is intricate too because one has to do it in such a way that the yellowish light does not blend with the blue to give a greenish effect. This is due to the way in which sun shows through the sky, but it is relevant to consideration of colour because objects often change shade by being seen through surfaces. Flouressent colour shades are interesting too, often created artificially, but they do create imaginary possibilities.
It is also interesting how the colour of blood changes from the blue of veins to red when a person bleeds, because oxygen comes into it. The colour of skin is interesting too because while people often speak of people being black or white, and of yellow as well, in actuality there is a whole multitude of shades and hues. Even within each of our bodies there are so many different areas of skin colour, mainly due to the thickness or thinness of skin in certain areas and blood flow variation.
It is also questionable if black is an actual colour. In some paint sets there is no black included because it is thought that it is possible to mix it from the other colours. When I tried this, I was not really satisfied with the result, because it didn't seem black enough. Another aspect arising when painting is the way the water gets discoloured by the dirty brushes, and as a child I used not to clean the brushes enough and this led to colours in the picture becoming a murky shade.