No reflected colour will have the brilliance of a direct one. For, if a reflected light from a blue object be thrown on a yellow one, the result would be green:—green being composed of blue and yellow. This circumstance refers to most mixtures.
It only happens to those colours which are on a level with the eye, that their gradation is in proportion to their distance. As to those of elevation, they are influenced by the quality of the air they are seen through.
Colours, whose nearest approach is to black, as they retire into distance, partake most of the azure of the air:—and those colours most dissimilar to black, preserve their proper colour as they recede. The golden lights on distant mountains or fields will best explain this. 'The green, therefore, of the fields will change sooner into blue, than yellow or white, which will preserve their natural colour at a greater distance than that, or even red.'
'It may happen that a colour does not alter, though placed at different distances, when the thickness of the air and the distance are in the same inverse proportion.'
Masses of shadow carry the strongest part of their colour to the greatest distance; as when trees appear thick together, accumulating the shadow on each other, they become darker by multiplying those shadows.
'The darker a mountain is in itself,' says Leonardo, 'the bluer it will appear at a great distance. The highest part will be the darkest, being more woody; because woods cover a great many shrubs and other plants, which never receive the light. Near the tops of those mountains, where the air is thinner and purer, the darkness of the woods will make it appear of a deeper azure than at the bottom, where the air is thicker.'
'In general, all objects that are darker or lighter than the air are discoloured by distance, which changes their quality, so that the lighter appears darker, and the darker lighter.'
Colours are more or less entirely lost at a great distance from the eye, according to the purity or density of the air through which they are revealed, or as they are more or less elevated from the earth, merging as they retire into a general grey, occasioned by the quantity of the intervening air. In countries where the air is thin, colours are discernible at great distances, but still tinged with the colour of that air.
The darkest colours, in distance, will be most of all impregnated with the colour of the air. So will the strongest real or accidental shadows.
Colours and outline are best defined on objects placed out of the strong light of the sun, and its reflexes. In sunshine, both are operated on by refraction, which occasions that chaotic indistinctness so painful for the eye to dwell on long together.