mattermorphosis

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The ancients admitted only three primary colours: yellow, red and blue, and the modern painters do not admit any others. In fact, these three colours are the only indissoluble and irreducible ones. Everybody knows that sunlight is made up of a series of seven colours, which Newton called primitive - violet, indigo, blue, green, yellow, orange and red; but it is clear that the appellation “primitive” cannot be applied to three of these colours, which are composite, for orange is got by mixing red and yellow; green, by mixing yellow and blue; and violet, by mixing blue and red. As to indigo, it cannot be counted among the primitive colours, for it is only a variety of blue. So in accordance with antiquity it must be acknowledged that there are only three colours which are truly elementary in nature, and which, when they are mixed two at a time, produce three more composite colours which may be called secondary, to whit: orange, green and violet.

These rudiments, developed by modern scientists, have led to the conjecture of certain laws that form an illuminating theory of colours, a theory which Eugène Delacroix commanded scientifically and thoroughly, after grasping it instinctively. (See his Grammaire des arts de dessin, 3rd ed. Renouard.) If one combines two of the primary colours, for instance yellow and red, in order to produce a secondary colour - orange - this secondary colour will attain maximum brilliancy when it is put close to the third primary colour not used in the mixture. In the same way, if one combines red and blue in order to produce violet, this secondary colour, violet, will be intensified by the immediate proximity of yellow. And finally, if one combines yellow and blue in order to produce green, this green will be intensified by the immediate proximity of red. Each of the three primitive colours is rightly called complementary with regard to the corresponding secondary colours. Thus blue is the complementary colour of orange; yellow, the complementary colour of violet; and red, the complementary colour of green. Conversely, each of the combined colours is the complementary colour of the primitive one not used in the mixture. This mutual intensification is what is called the law of simultaneous contrast.

When the complementary colours are produced in equal strength, that is to say in the same degree of vividness and brightness, their juxtaposition will intensify them each to such a violent intensity that the human eye can hardly bear the sight of it.

And due to a singular phenomenon, the same colours which strengthen each other by their juxtaposition will destroy each other when they are mixed. So if one mixes blue and orange in equal quantities, the orange will be as little orange as the blue is blue, the mixture destroys the two tints, and there emerges an absolutely colourless grey.

But if one mixes two complementary colours in unequal proportions, they only partially destroy each other, and one gets a broken tone, which will be a variety of grey. This being so, new contrasts may be born of the juxtaposition of two complementary colours, one of which is pure and the other, broken. As the fight is unequal, one of the two colours gains the victory, and the intensity of the dominant colour does not preclude the harmony of the two.

Now, if one brings together similar colours in a pure state but in different degrees of intensity, one gets another effect, in which there will be a contrast through the difference in intensity and at the same time harmony through the similarity of the colours. Finally, if two similar colours are placed next to each other, the one in a pure state, the other broken, for instance pure blue and grey-blue, another kind of contrast will result, which will be toned down by the analogy. So it is clear that there are various means, divergent among themselves, but equally infallible, by which to intensify, to maintain, to weaken or to neutralize a colour’s effect, and this by its reaction to the contiguous tones - by its touching what is not itself.

In order to intensify and to harmonize the effect of his colours he used the contrast of the complementary and the concord of the analogous colours at the same time; or in other terms, the repetition of a vivid tint by the same broken tone.

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Letter from Vincent van Gogh (citing Delacroix) to Theo van Gogh Nuenen, c. 13-17 April 1885