Some colours are rather unsociable, and, not mixing well with others, are best used by themselves, producing the required tint by glazing one over the other.
When any transparent colour is laid over an opaque one, or another of its own quality, it produces a mixture different to either of those that compose it; as lake over blue gives purple; yellow on blue produces green, and so on. In many cases this is a superior method to that of mixing them at once to the colour desired.
White is the receiver of all colours; black of none.
Any single colour appears most beautiful and brilliant when near the same colour, but not having so much density in it. Observe how colours are blended or contrasted in the plumage of birds, the wings of butterflies, &c.
The shifting, blending, and comparing a number of coloured cards, has always been found a useful and amusing way of instructing children in a knowledge of colours.
Different coloured pieces of glass held up against a landscape, will serve to show, through their medium, the varieties of hot and cold effects.
Certain colours impart value to others, principally by contrast; thus, the brilliant and rich glow of an autumnal evening is rendered most intense when the dark brown and neutral masses of foliage are brought up against it: it is only to their relative situations that they owe their power.
That part of a white object which is nearest to a dark one, will appear the whitest, and the less so as it is removed from it. The same occurs by a dark one.
All colours will appear most perfect in themselves when contrasted with their opposites—a green against red; blue against yellow; black against white, &c.
Where one colour terminates on another, that is its contrast, there will be greater strength exhibited at the junction than in the middle.