First Division: Physiological Colours · Zur Farbenlehre

From the Preface

It might well be asked whether one who wishes to speak of colours should not first speak of light. To this we answer briefly and frankly: since so much has already been said about light, it hardly seems needful to repeat it, or to add much to what has been repeated. For in reality we undertake in vain to express the nature of a thing. We perceive effects, and a complete history of those effects would, at all events, embrace the nature of the thing itself. Colours are the deeds of light: its deeds and its sufferings. In this sense we may expect from them some disclosure of the nature of light.

Colours and light stand, indeed, in the closest relation to each other; but we must think of both as belonging to nature as a whole, for it is nature as a whole that reveals itself through them to the sense of the eye. In the same way the whole of nature reveals itself to another sense. Nature speaks to all our senses, to known, unknown and unrecognised senses; so she speaks to herself and to us in a thousand ways.

The old theory, that colour lies hidden in white light, and is drawn out of it by the prism, is like an old castle, built by its founder with youthful haste, and since enlarged and strengthened by his successors with towers and bulwarks, until it is no longer habitable, but only defended. We do not mean to besiege it; we mean to show that one can live without it, in the open air.

From the Introduction

The eye owes its existence to light. Out of indifferent animal organs, light calls forth an organ that is its own likeness; so the eye is formed by light, for light, so that the inner light may meet the outer. Here we recall the old Ionian school, which said again and again that like is known only by like; and the words of an old mystic, which we may render thus:

Were the eye not of the sun, how could we look upon the light? Were not God's own strength within us, how could the divine delight us?

We shall consider colours under three heads. First, those that belong to the eye itself, and depend on its action and reaction: these we call physiological. Second, those we see in and by means of colourless media, transparent or turbid: these we call physical. Third, those that we can think of as belonging to objects, and fixed in them: these we call chemical.

Light and darkness, brightness and obscurity, or, if one prefers a more general expression, light and its absence, are needed to produce colour. Next to light, a colour appears which we call yellow; next to darkness, another, which we call blue. When these two are mixed in their purest state, so that they balance each other exactly, they produce a third colour, which we call green. But each of the two first colours can also, by being condensed or darkened, produce a new appearance in itself: they take on a reddish look, which can increase to such a height that the original blue or yellow is hardly recognisable. And when the yellow-red and the blue-red extremes are united, there arises the most intense, the most splendid colour, which we call purple. These are the simplest elements of the whole theory.

Physiological Colours

We place these colours first, because they belong wholly, or largely, to the subject: to the eye. They are the foundation of the whole doctrine, and they reveal to us the harmony of colour about which there has been so much dispute. Earlier writers treated them as something outside nature, as accidental — illusions, deceptions of sight, phantoms. We call them physiological, because they belong to the healthy eye, and because we regard them as the necessary conditions of vision.
If the eye is kept in darkness, it demands light: it is in a state of increased receptivity. If it is exposed to a bright white surface, it is dazzled, and for a time it cannot distinguish moderately lighted objects.
To see, the eye must have the brightest light it can bear beside the deepest darkness; it is always seeking to produce one in the presence of the other.
A dark object appears smaller than a bright one of the same size. Let a white disc on a black ground and a black disc on a white ground be compared: the black will seem about a fifth smaller.
If one looks for a while at a window, with the bright sky behind it, and then closes the eyes, or looks into a dark part of the room, one sees the cross of the window frame light against a dark ground: an after-image, in which the dark and light are reversed. It shrinks, fades, and loses its outline before it vanishes.
The eye cannot remain for a moment in one particular state determined by the object it looks at. It is forced to a kind of opposition, which, by setting extreme against extreme, intermediate against intermediate, at the same time combines these opposite impressions, and always strives towards a whole. Here we see the eternal formula of life itself: to separate and unite, to inhale and exhale.
A grey patch on a black ground appears much brighter than the same patch on a white ground.
If one looks, in a darkened room, at a round bright opening through which the sun is shining, and then closes the eyes, the after-image of the bright circle remains, and passes through colours: its rim turns red, then blue, then dark, before it vanishes.
If we look at a coloured object, the after-image is coloured with the opposite colour: yellow calls forth violet; orange, blue; purple, green; and the reverse.
I was sitting one evening in an inn, when a pretty girl, with a brilliantly fair face, black hair and a scarlet bodice, came into the room. I looked at her intently as she stood at some distance from me in the half-light. When she moved away, I saw on the white wall opposite a dark face, surrounded by a bright light, and the clothes of the perfectly distinct figure were a beautiful sea-green.
At dusk, flowers seem to flash: the oriental poppy, the marigold, give off, as it were, little lights; but these are the after-images in the eye, called up by their bright colour against the darkening ground.
A small piece of white paper on a yellow wall seems to have a violet tint; on a green ground, a reddish one. The eye, faced with one colour, at once produces the other that completes it.
These are the colours that the eye demands. The eye demands completeness, and seeks to round off the circle of colour in itself. In the violet, called up by the yellow, are united the red and blue that the yellow lacks. Here we have the principle of the harmony of colour: if the colours the eye demands are given to it, it is satisfied.
If a lighted candle is placed, at twilight, on a white paper, and an upright pencil set between it and the fading daylight, the shadow cast by the candle, lit by the faint blue daylight, appears of the most beautiful blue. Here the colour of the shadow is the colour the eye demands in answer to the yellow-red candlelight that tints the paper.
Coming down the Harz one winter evening, as the sun was setting, I saw the shadows on the snow, which had been bluish all day, become a beautiful green as the sky reddened; the light was purple, and the shadows answered with green.
A strong light appears white; a weaker one tends to colour. A candle near the eye seems yellow; in daylight it looks reddish; a flame at a distance looks red.
Around bright objects the eye sees halos; these vanish when the light is covered, and so they belong to the eye, not to the light. The disturbance spreads out from the bright image like rings on water, or like the trembling of a struck bell.

Goethe adds to this division an account of pathological colours: the colour-blindness of certain observers, who cannot tell blue from pink, or see the green of the trees as the red of a rose; and the colours that appear to sick or injured eyes.