visual perception of light wavelengths
(Redirected from Colours)

Color (North American English) or colour (Commonwealth English) is the visual perceptual property corresponding in humans to the categories called red, blue, yellow, etc. Color derives from the spectrum of light (distribution of light power versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects or materials based on their physical properties such as light absorption, reflection, or emission spectra. By defining a color space colors can be identified numerically by their coordinates.

64 365 Color Macro (5498808099).jpg


Desert Joshua Tree
at Sunset
  • [P]ure light, such as that from the sun has no color, but is made colored by its degradation when interacting with objects having specific properties which then produce color.
    • Aristotle (c. 350 BC) as quoted by Kurt Nassau, The Physics and Chemistry of Color: The Fifteen Causes of Color (1983) p. 4.
  • [L]ight the colour of the transparent medium contingently determined; for when anything of the nature of fire is found in the transparent medium its presence constitutes light, its absence darkness. ...[T]he transparent element is nothing which is found exclusively any one of the substances ...finds its existence in these bodies and subsists in varying degrees in the rest of material substances. ...[T]he Pythagorean terminology identified the visible superficies with colour. ...[C]olour exists in the boundary, but it by no means is the boundary of the body ...internally there exists the same constitution as externally displays colour. ...Colour the limit of the transparent element in a determinately bounded body ...both in transparent substances ...and in those which appear to have a surface colour of their own. ...[T]hat, which in air causes light, may be present in the transparent medium or it may not ...[W]hite and black may be juxtaposed in such a way that by the minuteness of the division of its parts each is invisible while their product is visible, and thus colour may be produced. This product can appear neither white nor black must be a sort of compound and a fresh kind of tint. ...[C]olours ...may be produced, and ...their multiplicity is due to differences in the proportion of their composition. ...[C]olours may analogous to harmonies. ...[T]hose compounded according to the simplest proportions is the case in harmonies, will appear to be the most pleasant ...e.g. purple, crimson ...This is one of the ways in which colours may be produced; a second is effected by the shining of one colour through another. This we may illustrate by the practice painters when they give a wash of colour over another more vivid tint, when, for example, they wish to make a thing look as though it were in the water or in the air. ...[W]e may illustrate by the sun, which in itself appears white, but looks red when seen through mist and smoke. ...[W]e should have to suppose there was some ratio between the superficial and the underlying tints in ...some colours, while in others there would be ...lack of commensurate proportion. ...[Thus is absurd to maintain, with the early philosophers, that colours are effluxes and that vision is effected by a cause of the efflux type. It was in every way binding on them to account for sensation by means of contact, and therefore it was obviously better to say that sensation was due to a movement set up by the sense object in the medium of sensation, and thus account for it by contact without the instrumentality of effluxes.]
    According to the theory of juxtaposition, just as we must assume that there are invisible spatial quanta, so must we postulate an imperceptible time to account for the imperceptibility of the diverse stimuli transmitted to the sense organ... But on the other theory there is no such necessity; the surface colour causes different motions in the medium when acted on and when not acted on by an underlying tint. Thus it appears to be something different, and neither black nor white. ...But let us premise that substances are mixed not merely in the way some people think by a juxtaposition of their ultimate minute parts ...imperceptible to sense but that they entirely interpenetrate each other in every part throughout ...The former theory accounts for the mixture only of those things which can be resolved into ultimate least parts ...On the other hand, things which cannot be resolved into least parts, cannot be mingled in this way; they must entirely interpenetrate each other; and these are the things which most naturally mix. ...[W]hen substances are mixed their colours too must be commingled, and that this is the supreme reason why there is a plurality of colours; neither superposition nor juxtaposition is the cause. In such mixtures the colour does not appear single when you are at a distance and diverse when you come near; it is a single tint from all points of view. The reason for the multiplicity of colours will be the fact that things which mix can be mixed in many different proportions ...[T]he same account will apply to the juxtaposition or superposition of colours as to their mixture. [T]hey, and likewise tastes and sounds, have definite species limited in number...
  • The colors of my life
    Are bountiful and bold,
    The purple glow of indigo,
    The gleam of green and gold.
    The splendor of the sunrise,
    The dazzle of a flame,
    The glory of a rainbow,
    I'd put 'em all to shame.
Transfiguration (1350)
  • When Michael saw this host, he first grew pale,
    As angels can; next like Italian twilight,
    He turned all colours—as a peacock's tail,
    Or sunset streaming through a Gothic Skylight
    In some old abbey, or a trout not stale,
    Or distant lightning on the horizon by night
    Or a fresh rainbow, or a grand review
    Of thirty regiments in red, green, and blue.
  • From the mingled strength of shade and light
    A new creation rises to my sight,
    Such heav'nly figures from his pencil flow,
    So warm with light his blended colors glow.
    • Lord Byron, Monody on the death of the Rt. Hon. R. B. Sheridan, Stanza 3. In Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 576-77.
Invocation (Vestal)
Frederic Leighton (1880)
  • Once a pallid vestal
    doubted truth in blue;
    Listed red as ruin,
    Harried every hue;

    Barracaded vision,
    garbed herself in sighs;
    Ridiculed the birth marks
    Of the butterflies

    Dormant and disdainful,
    Never could she see
    Why the golden powder
    Decorates the bee;

    Why a summer pasture
    Lends itself to paint;
    Why love unappareled
    Still remains the saint.

    Finally she faltered;
    Saw at last forsooth,
    Every gaudy color
    Is a bit of truth.

  • ...I am always between two currents of thought, first the material difficulties, turning round and round to make a living; and second, study of color. I am always in hope of making a discovery there, to express the love of two lovers by a marriage of two complementary colors, their mingling and their opposition, the mysterious vibrations of kindred tones. To express the thought of a brow by the radiance of a light tone against a sombre background. To express hope by some star, the eagerness of a soul by a sunset radiance. Certainly there is nothing in that of stereoscopic realism, but is it not some thing that actually exists?
  • In nature, light creates the color; in the picture, color creates light. Every color shade emanates a very characteristic light — no substitute is possible.
    • Hans Hofmann, as quoted in Readings in American art, 1900 -1975 (1975) by Barbara Rose, p. 117
    • Variant: In nature, light creates the color. In the picture, color creates the light.
Layers of the Eye
  • Color is that aspect of the appearance of objects and lights which depends upon the spectral composition of the radiant energy reaching the retina of the eye and upon its temporal and spatial distribution thereon.
    • Dean B. Judd, Introduction to Color, Symposium on Color—Its Specification and Use in the Evaluation of Materials (March 5, 1941) American Society for Testing Materials, Washington Spring Meeting. STB50-EB/Jul. 1941, p. 1.
  • I mix them with my brains, sir.
    • John Opie, when asked with what he mixed his colors. See Samuel Smiles, Self Help, Chapter V. In Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 576-77.
  • Loudness depends on the quantity of the sound. Of the harmony of sounds I will hereafter speak.
    Colors are a flame which emanates from all bodies having particles corresponding to the sense of sight. Some of the particles are less and some greater, and some are equal to the parts of the sight. The equal particles are transparent, the larger contract, and the lesser dilate the sight; white is produced by the dilatation, black by the contraction, of the particles of sight. There is also a swifter motion of another sort of fire which forces a way into the passages of the eyes, and elicits from them a union of fire and water which we call tears. The fires from without and within meet and are extinguished in the tear-drop, and all sorts of colors are generated in the mixture. This affection is termed by us dazzling, and is produced by a flash. There is yet another sort of fire which mingles with the moisture of the eye without flashing, and produces a color like blood—to this we give the name of red. Again, the bright element mingling with the red and white produces a color which we call auburn. The law of proportion, however, in which the several colors are formed, cannot be determined scientifically or even probably. Red, when mingled with black and white, gives a purple hue, which becomes umber when the colors are burnt and a greater portion of black is added. Flame-color is a mixture of auburn and dun; dun of white and black; pale yellow of white and auburn. White and light meeting, and falling upon a full black, become dark blue; dark blue mingling with white becomes a light blue; the union of flame-color and black makes leek-green. There is no difficulty in seeing how other colors are probably composed. But he who should attempt to test the truth of this in fact, would forget the difference of the human and divine nature. God only is able to compound and resolve substances; such experiments are impossible to man.
  • I've fought the good fight. And now it’s all over, there's an indescribable peace. ...I believe in Michelangelo, Velásquez and Rembrandt; in the might of design, the mystery of color, the redemption of all things by beauty everlasting and the message of Art that has made these hands blessed. Amen. Amen.
  • If you mean that the proximity of one color should give beauty to another that terminates near it, observe the rays of the sun in the composition of the rainbow, the colors of which are generated by the falling rain, when each drop in its descent takes every color of the bow.

De Coloribus (c. 300 B.C.)Edit

On Colors (Greek Περὶ χρωμάτων) is attributed to Aristotle, but ascribed to Theophrastus or Strato of Lampsacus by some authorities. Tr. (1913) by T. Loveday & E. S. Forster in The Works of Aristotle (1913) ed. W. D. Ross, Vol VI.
  • Simple colours are the proper colors of the elements, i.e., of fire, air, water, and earth. Air and water when pure are by nature white, fire (and the sun) yellow, and earth is naturally white.
  • There are many arguments to prove that darkness is not a colour, but merely privation of light...
  • From these primary colours the rest are derived in all their variety of chromatic effects by blending of them and by their presence in varying strengths. ...[M]ixture of white with black, which gives grey. ...[A] dusky black mixed with light gives crimson. ...[A] vivid bright violet is obtained from a blend of feeble sunlight with a thin dusky white. That is why the air sometimes looks purple at sunrise and sunset... So, too, the sea takes a purple hue when the waves rise so that one side of them is in shadow...
  • [W]e must not proceed in this inquiry by blending pigments as painters do, but rather by comparing the rays reflected from the aforesaid known colours, this being the best way of investigating the true nature of colour-blends.
  • [V]ariations of tint occur: 1) Because colours are introcepted by varying and irregular strengths of light and shade. ...(2) because the colours blent vary in fullness and in effectiveness. ...(3) because they are blent in different proportions. ...(4) Difference of hue may also depend on the relative brightness and lustre or dimness and dullness of the blend. Lustre is simply continuity and density of light... (5) some objects change their colour and assume a variety of hues when polished by rubbing or other means, like silver, gold, copper, and iron, when they are polished...(6) In the case of objects burning, dissolving, or melting in the fire, we find that those have the greatest variety which are dark in colour... (7) Apart from these cases, variety of hue is characteristic of all dark smooth objects, such as water, clouds, and birds plumage. ...(8) Lastly, we never see a colour in absolute purity: it is always blent, if not with another colour, then with rays of light or with shadows, and so it assumes a new tint.
  • [O]bjects assume different tints ...when seen by firelight or moonlight or torchlight, because the colours of those lights differ some what. They vary also in consequence of mixture with other colours, for when coloured light passes through a medium of another colour it takes a new tinge.
  • [L]ight when it reaches the eye may be a blend of many colours, though the sensation produced is not of a blend but of some colour, predominant in the blend. This is why objects under water tend to have the colour of water, and why reflections in mirrors resemble the colour of the mirrors, and we must suppose that the same thing happens in the case of air.
  • Thus all hues represent a threefold mixture of light, a translucent medium (e.g. water or air), and underlying colours from which the light is reflected.
  • Coloration may also be due to a process of tincture or dyeing, when one thing takes its hue from another. Common sources of such coloration are the flowers of plants and their roots, bark, wood, leaves, or fruit, and 20 again, earth, foam, and metallic inks. Sometimes coloration is due to animal juices (e.g. the juice of the purple- fish, with which clothes are dyed violet), in other cases to wine, or smoke, or lye mixture, or to sea-water... In short, anything that has a colour of its own may transfer that colour to other things, and ...colour leaving one object passes with moisture and heat into the pores of another... Furthermore, steeping material to be dyed in different astringent solutions during the dyeing produces a great variety of hues and mixtures, and these are also affected by the condition of the material itself...

Letters of a Post-Impressionist (1912)Edit

:Being the Familiar Letters of Vincent van Gough Tr. Anthony M. Ludovici. [Note: quotes below are for the most part, from letters written during his period as an active painter, between 1882 and 1890, the year of van Gough's death.]
Portrait of the Artist's Mother (1888)
  • I am at work upon a portrait of our mother; as I could no longer endure the sight of the black photograph. I do not wish to possess black photographs, and yet I certainly wish to have a portrait of our mother.
The Red Vineyard (1888)
  • Dear Brother, ...Last Sunday I began something which I had had in mind for many a day:
    It is the view of a flat green meadow, dotted with haycocks. A cinder path running alongside of a ditch crosses it diagonally. And on the horizon, in the middle of the picture, there stands the sun. The whole thing is a blend of colour and tone a vibration of the whole scale of colours in the air. First of all there is a mauve tinted mist through which the sun peers, half concealed by a dark violet bank of clouds with a thin brilliant red lining. The sun contains some vermilion, and above it there is a strip of yellow which shades into green and, higher up, into a bluish tint that becomes the most delicate azure. Here and there I have put in a light purple or gray cloud gilded with the sun's livery.
    The ground is a strong carpet-like texture of green, gray and brown, full of light and shade and life. The water in the ditch sparkles on the clay soil. It is in the style of one of Emile Breton's paintings.
    I have also painted a large stretch of dunes. I put the colour on thick and treated it broadly.
    I feel quite certain that, on looking at these two pictures, no one will ever believe that they are the first studies I have ever painted. ...I believe the reason of it is that before I began to paint, I made such a long and careful study of drawing and perspective that I can now sketch a thing as I see it. ...[S]ince I have bought my brushes and painting materials, I have slaved so hard that I am dead tired—seven colour studies straight off! ...I literally cannot stand, and yet I can neither forsake my work nor take a rest. ...[W]hen I am painting things present themselves to me in colour, which formerly I never used to see things full of breadth and vigour. ...I have progressed to the extent that when anything in Nature happens to strike me, I have more means at my command ...for expressing that thing with force.
Avenue in Park d'Argenson in Asnierès (1887)
A Woman Walking in a Garden
Acacia in Flowers
  • Yesterday evening I was busy painting the gently rising ground in the wood, which is all strewn with dry withered beach leaves. It varied in colour from a light to a dark red-brown, and the cast shadows of the trees fell across it in faint or strongly marked stripes. The difficulty was and I found it very trying to succeed in getting the depth of the colour and the enormous strength and solidity of the ground and I noticed while I worked how much light there was even in the dark shadows! The thing was to render the effect of light and also the glow, and not to lose the depth of rich colour. For one cannot imagine a more magnificent carpet than that deep red-brown ground, bathed in the glow of the autumn evening sunlight, softened by its passage through the trees.
    Beech trees grow here, the trunks of which look bright green in the clear light and a warm black-green in the shade. Behind the trunks, above the red-brown ground one could see the delicate blue and warm gray of the sky—it was scarcely blue—and in front of it a diaphanous haze of green, and a maze of trees with golden leaves. The forms of a few peasants gathering wood crept about like dark mysterious shadows, while the white bonnet of a woman bending to gather a few dried twigs suddenly stood out from the deep red-brown of the earth. ...The white bonnet, the shoulders, and bust of a woman stood out against the sky. The figures were large and full of poetry and, in the twilight of the deep shadows, seemed like gigantic terracottas fashioned in a studio. That is how I describe Nature to you. How far I have rendered the effect in my sketch, I do not know. I can only say that I was struck by the harmony of green, red, black, yellow, blue, and gray. It was quite in the style of de Groux; the effect was like that in the sketch of the "Depart du Consent."
    To paint it was a herculean task. On the ground alone I used one and a half large tubes of white; and yet it is still very dark. I also used red, yellow, brown, yellow-ochre, black, raw sienna and bistre and the result is a red-brown, which varies from a deep wine-red to a delicate pale pink. It is very difficult to succeed in getting the colour of the moss and the effect of the small border of fresh grass which shone so brightly in the sunlight. Believe me, this is a sketch which, if I may say so, people will think something of, for it makes a decided appeal. ...I pressed the roots and trunks out of the tubes direct, and then modelled them a little with the brush. And now they do indeed stand in the soil, and grow out of it, and strike firm roots into it. ...In a sense I am glad that I never learnt to paint. If I had I should perhaps have learnt to overlook such effects.
  • The great doctrine bequeathed to us by the Dutch masters is, I think, as follows: Line and colour should be seen as one, a standpoint which Bracquemond also holds. But very few observe this principle, they draw with everything, save with good colour.
The Wedding Feast at Cana,
Paolo Veronese (1563)
  • [W]hile contemplating Hals, Rembrandt, Ruysdael, and others, I constantly thought of the saying, that when Delacroix paints, it is exactly like a lion devouring a piece of flesh. How true that is! And, Theo, when I think of what one might call "the technique crew" how tedious they all are! ...For is it not exasperating to see the same dodges everywhere... everywhere the same tedious gray-white light, in the place of light and chiaroscuro, colour, local colour instead of shades of colour...
    Colour as colour means something ...That which has a ...really beautiful effect, is also right. When Veronese painted the portraits of his beau monde in the "Marriage at Cana," he used all the wealth of his palette in deep violets and gorgeous golden tones for the purpose, while he also introduced a faint azure blue and a pearly white which do not spring into the foreground. He throws it back, and it looks well in the neighbourhood of the sky and of the marble palaces, which strangely complete the figures; it changes quite of its own accord. The background is so beautiful that it seems to have come into being quite naturally and spontaneously out of the colour scheme. ...The point is to think about a thing, to consider its surroundings, and to let it grow out of the latter. ...I do not wish to argue studying from Nature or the struggling with reality, out of existence; for years I myself worked in this way with almost fruitless and, in any case, wretched results. ...One begins by plaguing one's self to no purpose in order to be true to nature ...But these two methods cannot be pursued together. Diligent study, even if it seem to be fruitless, leads to familiarity with nature and to a thorough knowledge of things.
    The greatest and most powerful imagination has also been able to produce things from reality, before which people have stood in dumb amazement.
Vincent's Bedroom in Arles (1888)
  • I will simply paint my bedroom. This time the colour shall do everything. By means of its simplicity it shall lend things a grand style, and shall suggest absolute peace and slumber... The walls are pale violet, the floor is covered with red tiles, the wood of the bed and of the chairs is a warm yellow, the sheets and the pillow are a light yellow-green, the quilt is scarlet, the window green, the washstand is orange, the wash-basin is blue, and the doors are mauve. That is all there is nothing more in the room... As there is no white in the picture, the frame should be white. This work will compensate me for the compulsory rest to which I have been condemned. ...Shadows and cast shadows are suppressed, and the colour is rendered in dull and distinct tones like crape of many colours.
The Night Café
  • I should like to make copies of "The Tarascon Diligence," "The Vineyard, "The Harvest," and "The Red Cabaret," especially of the night café, for its colouring is exceptionally characteristic. There is only one white figure in the middle which will have to be painted in afresh and improved in drawing, although it is good as far as its colour is concerned. The South really looks like this, I cannot help saying so. The whole scheme is a harmony in reddish green.
    I do not need to go to the Museum and to see Titian and Velasquez. I have studied my trade in Nature's workshop, and now I know better than I did before I took my little journey, what is above all necessary if one wishes to paint the South. Heavens! what fools all these painters are! They say that Delacroix does not paint the Orient as it is. Only Parisians—Gerome, etc.—can paint the Orient as it is—is that their claim? It really is a funny thing, this business of painting, out in the wind and the sun. ...[O]ne simply sets to like mad, as if the devil himself were at one's back, until the canvas is covered. It is precisely in this way that one discovers what everything depends upon. And this is the whole secret. ...[O]ne ...introduces something of one's own good cheer and laughter into it.
Self-Portrait (1889)
  • [I]nstead of reproducing exactly what I see before me, I treat the colouring in a perfectly arbitrary fashion. ...What I aim at above all is powerful expression. ...Just suppose that I am to paint the portrait of an artist friend—an artist who dreams great dreams and who works as the nightingale sings, simply because it it is his nature to do so. ...All the love I feel for him I should like to reveal in my painting ...To begin with ...I paint him just as he is, as faithfully as possible still this is only the beginning. ...Now I begin to apply the colour arbitrarily. I exaggerate the tone of his fair hair; I take orange, chrome, and dull lemon yellow. Behind his head, instead of the trivial wall of the room I paint infinity. I make a simple background out of the richest of blues, as strong as my palette will allow. And thus, owing to this simple combination, the fair and luminous head has the mysterious effect, upon the rich blue background, of a star suspended in dark ether. ...But one ought to picture this sort of fellow in the scorching noonday sun, in the midst of the harvest. Hence this flaming orange, like a red-hot iron; hence the luminous shadows like old gold. ...[W]e wish to show that this reading has become part of our flesh and blood.
    I can only choose between being a good and a bad painter. I choose the former.
  • One cannot be at the Pole and at the Equator at once. One must choose one's way; at least this is what I hope to do, and my way will be the road to colour.

The Physics and Chemistry of Color: The Fifteen Causes of Color (1983)Edit

by Kurt Nassau
  • The blue dye indigo is one of the oldest dyes known to man, having been in use for more than 4000 years. Its preparation by complex extraction processes was described in Sanskrit writings, and it was used to dye Egyptian mummy cloth. When Julius Caesar invaded Britain in 55 B.C., he found that the local Picts ("painted people") decorated themselves with woad, a form of indigo. And who, today, does not know the all-pervading blue jeans, frequently dyed with the same indigo, now manufactured synthetically. While the transition metal colors... can be adequately explained by ligand field theory, the all-encompassing molecular orbital theory is required to explain the color of organic molecules. These include dyes and pigments, both as they occur in nature as colorants in the animal and vegetable kingdoms from which they were first extracted, and also as the triumphs of the synthetic dye industry which have displaced natural dyes almost completely. ...[W]e use the term "colorant" to include all types of organic dyes and pigments involving electrons on more than one atom in organic molecules, while multi-atom color-producing systems involving charge transfer are deferred ...
    • Ch. 6 Color in Organic Molecules, p. 109.
  • A crystal of corundum containing a few hundredths of one percent of titanium is colorless. If, instead it contains a similar amount of iron, a very pale yellow may be seen. If both impurities are present together, however, the result is a magnificent deep blue color, that of blue sapphire... The process at work is intervalence charge transfer, the motion of an electron from one transition metal to another produced by the absorption of light energy; this results in a temporary change in valence state of both ions. Such a mechanism is the cause of the blue sapphire and the black and dark colors of many transition metal oxides such as iron oxide magnetite Fe3O4. The mechanism is sometimes also called cooperative charge transfer.
    Somewhat analogous charge transfer processes also occur in ligand field situations; this can lead to color even if there are no unpaired electrons to cause the color by... transition mechanisms... [I]t is possible to describe many of the donor-acceptor dyes... as involving charge transfer, although... not commonly used.
    • Ch. 7 Charge Transfer Color, p. 140.
  • [S]emiconductors as silicon are distinct from metals, yet the properties of both are readily explained by the same band theory. ...[T]he semiconducting properties of this metalic-appearing silicon and the absence of color and insulating properties of, say, diamond, are both part of a continuous range of materials which unexpectedly includes the red, orange, and yellow colors of medium band-gap semiconductors. ...It is the delocalized nature of the valence electrons, their ability to move freely throughout a piece of metal or semiconductor, which is at the root of the characteristics of these two types of material.
    • Ch. 8 Color in Metals and Semiconductors, p. 155.

See alsoEdit

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