Visual contrast

“ Nor is it at all difficult to understand how this general condition comes to be associated with the eye, and how the particular visual sensations come to be associated with something distant from the eye: and further, how this association of the condition with one thing, and of the sensations with another thing, (an association established by the touch and not by the sight,) dissolves the primary synthesis of seeing and colours. ”

“ In which case we should have remained blind, or as bad as blind; brightness would have been in the eye when it ought to have been in the sun; greenness would have been in the retina when it ought to have been in the grass. A most wise provision of nature it certainly is, by which our visual sensations are disposed of in the right way before we obtain any knowledge of the eye. ”

“ All those operations, therefore, which proceed from direct irritation of the nervous part of the visual organ, without the medium of the eye and of light, under the term subjective vision, are opposed to those phenomena produced by the media of eye and light, and known as objective vision. ”

“ To obtain the best contrast-effects, therefore, the contracting fields should be near together, should not be separated by shadows or black lines, should be of homogeneous texture, and should be of about equal brightness and medium intensity of color. Such conditions do not often occur naturally, the disturbing influences being present in case of almost all ordinary objects, thus making the effects of contrast far less evident. ”

“ It is not merely the outward mechanism and motion of the eyelids, nor the colour of the eyes, that constitutes their beauty; we have already said that the leading characteristic of the eye was expression. It is this expression which causes the eye to appear to speak, to fire up suddenly, to sparkle with flashes of light, to languish or conceal itself underneath its lashes, to raise itself with inspiration, or to pierce the abyss of thought, just according to the particular sentiment governing the mind at the moment. ”

“ The substitution of simultaneous retinal perception of form for successive perception has the effect of bringing together the terms of the relations of variety and contrast, unity and similarity, under what is approximately one act of attention. If we watch the movements of a painter's hand as he draws the outline of a human figure on a canvas, our eye may attain a rough perception of the successive directions and distances ”

“ We will return, for the sake of simplicity, to the sense of sight, which we chose as our example.The result of positing sensations and then constructing perception with them. Psychology has accustomed us to assume the elementary sensations corresponding to the impressions received by the rods and cones of the retina. With these sensations it goes on to reconstitute visual perception. ”

“ Within the limits of clear perception, the intensity of brightness, and probably also of color contrast, increases proportionally to the linear extent of the inducing part of the retina, or to the square root of the surface content. A less intensity of correspondingly larger extent does not change the strength of the contrast. Color contrast is best, when brightness contrast is excluded and there is a combination of medium degrees of saturation of the colors. ”

“ Now, as has frequently been said, we cannot associate colours or the visual sensations with this eye; for these have been already disposed of otherwise. What, then, do we associate with it—and how? We find, upon experiment, that our apprehension of the various visual sensations depends on the presence and particular location of this small tangible body. We find that the whole array of visual phenomena disappear when it is tactually covered, that they reappear when it is reopened, and so forth. Thus we come in some way to associate vision with it—not as colour, however, not as visual sensation. ”

“ If his eyes have been fixed on some hallucinatory color, such as red, for instance, he will even give you a detailed account of the green he sees, but if he does not know anything of the effects of contrast colors no amount of fixation on hallucinatory colors will bring out the least contrast effects. ”

“ Experience points out the eye, and the eye alone, as the visual sensation essential to our apprehension of all our other sensations of vision, and we come at last to regard this sensation as the sense itself. Inveterate association leads us to regard the eye not merely as the organ, but actually as the sense of vision. We find from experience how much depends upon its possession, and we lay claim to it as a part of ourselves with an emphasis that will not be gainsaid. ”

“ An eye critically nice can only be formed by observing well-coloured pictures with attention; and by close inspection, and minute examination, you will discover, at last, the manner of handling, the artifices of contrast, glazing, and other expedients, by which good colourists have raised the value of their tints, and by which nature has been so happily imitated. ”

“ And since the pupil of the eye receives Within itself one kind of blow, when said To feel a white hue, then another kind, When feeling a black or any other hue, And since it matters nothing with what hue The things thou touchest be perchance endowed, But rather with what sort of shape equipped, 'Tis thine to know the atoms need not colour, But render forth sensations, as of touch, That vary with their varied forms. ”

“ In visual perception the sweep of the glance, that is the adjustment of the muscles of the inner eye, the outer eye and of the head, is susceptible of being either interrupted or continuous like any other muscular process; and its continuity is what unites the mere successive sensations of colour and light into a unity of extension, so that the same successive colour-and-light-sensations can be experienced either as one extension, or as two or more, according as the glance is continuous or interrupted ”

“ Contrast has a large influence in the idea of polish, which is not given as sensation, but is a product of the combinations of sensations. Emotional contrast is not independent of contrast in brightness and quality, but it determines the aesthetic effect of the colors and their combinations as a result of simultaneous contrast of the sensations. The maximum emotional effect is reached when color, brightness, and saturation are properly contrasted. ”

“ This is the interesting side of visual perception, that, owing to the vast complex of distinguishable sensations of light and colour of various qualities and intensities, together with the muscular sensations attending the varying positions of the organ, the eye is able to recognize at any instant a whole external world with its fundamental properties and relations. ”

“ When colored surfaces are placed near each other and compared in a natural manner, successive contrast plays an important part, and the appearance of the colors is more or less modified according to its laws. If we attempt to confine our attention to only one of the colored surfaces, this still holds good, for the eye involuntarily wanders to the other, and to prevent this requires a good deal of careful practice, for fixed vision is quite opposed to our natural habit. ”

“ By imagining the sight as a sensation of colour, we diminish it to a speck within the sphere of its own sensations; and as we now regard the sense as for ever enclosed within this small embrasure, all the other sensations which were its, previous to our discovery of the organ, and which are its still, are built up into a world of objective existence, necessarily external to the sight, and altogether out of it's control. All sensations of colour are necessarily out of one another. ”

“ But by attention we may easily discover the general facts involved in contrast. We find that in general the color and brightness of one object always apparently affect the color and brightness of any other object seen simultaneously with it or immediately after. ”

“ As a matter of fact, a highly trained eye can discover about a thousand different tints in the spectrum of white light. Time will not allow us to enter into any discussion of what is called colour-vision and the theory of sensations of colour. ”

“ Light and shade, colour, novelty, variety, contrast, and even simplicity, all become defects in their excess!—the spirit of the rules by which they are regulated is to be more observed than their literal sense. ”

“ Whatever be the term, which we may use, however, there is, and must be, a sensation peculiar to touch, without regard to the extent or quantity of the surface impressed,—as there is, in colour, a sensation peculiar to vision, without regard to the extent of the portion of the retina on which the light may have fallen. ”

“ Immediately over the pupil of the eye we find the faculty of Vision or sense of Sight, marked Light, which runs into a sense of Shade at the inner angle of the eye, by which two perceptions everything in nature except colors is recognized. Light extends up into Color. ”

“ Surely, then, when the sight is subsumed under the category of colour—as it unquestionably is whenever we think of the eye—surely all other colours must, of necessity, assume a position external to it; and what more is wanting to constitute that real objective universe of light and glory in which our hearts rejoice? ”

“ CHAPTER XIV - IMAGINATION AS AN AID TO VISION
WE see very largely with the mind, and only partly with the eyes. The phenomena of vision depend upon the mind's interpretation of the impression upon the retina. What we see is not that impression, but our own interpretation of it. Our impressions of size, color, form and location can be demonstrated to depend upon the interpretation by the mind of the retinal picture. ”

“ And, as I fixed my attention upon them more and more closely, heaven aid me! the features of a human face grew more and more distinctly traceable and visible, just as when, on looking at a distorted picture through a lens specially constructed, all its lines and effects then, and not till then, grow clear and sharp. ”

“ If we assume, on the other hand, that the movements and their feelings are alone possessed of the extensive quality, we make an unjustified hypothesis, for the phenomena compel us, it is true, to accord an influence to movement, but give us no right to call the retinal sensations indifferent, for there are no visual ideas without retinal sensations. ”

“ Further favorable stimulation of the eye is given in the method of the Impressionists in treating "values," that is, comparative relations of light and shade. The real tones of objects including the sky, light, etc., can never be reproduced. ”

“ Nor are the phenomena of broken reflections inferior in beauty and suggestion. Instead of motionless repetition of given detail, there are flickering, sinuous, mazy windings and twistings of colour, light, and shadow—a capricious hurrying from surface to surface. Knowledge of optics cannot rob them of their marvel and their glamour. ”

“ The sensation of sight coming from this retinal image unaided by other sensations gives us but two qualities, light and color. The eye can distinguish many different grades of light from purest white on through the various grays to densest black. The range is greater still in color. ”

“ The reason is that subconsciously we accompany visual experiences with tone-sensations, and vice versa. Cases are even known of human beings in whom the secondary sensation occurs with such intensity as to equal the primary one. Such people say that they 'see' sounds and 'hear' colours. ”

“ Yet philosophy has ascertained that we derive nothing from the eye whatever but sensations of color.... How, then, is it that we receive accurate information, by the eye, of size and shape and distance? By association merely. ”

“ The same effect may be observed when looking at the setting sun, or a flaring gas light. If the light at which we look is coloured, we shall see the complementary colour in the impression left on the retina. ”

“ EXPRESSIONS OF THE EYE.—The mere expression of the eye conveys precise ideas of the existing and predominant states of the mentality and physiology. As long as the constitution remains unimpaired, the eye is clear and bright, but becomes languid and soulless in proportion as the brain has been enfeebled. ”

“ Still, upon the whole, the effects of contrast with brilliant colors are often not strongly marked at first glance, from the circumstance that the colors, by virtue of their actual intensity and strength, are able to resist these changes, and it often requires a practiced eye to detect them with certainty. ”

“ We may, therefore, assume that colors possess objective differences, and that these objective differences are perceived even by persons of normal vision. But whether I am able to sense the same effect in red that another senses, and whether I should not call red blue, if I had the color-vision of another, is as impossible to discover as it is useless. ”

“ So long as the eyes continue to roll aimlessly about, and before they begin to focus accurately, they are more likely concerned with distinctions between light and shadow, than with perceptions of form or size. ”

“ So, in the natural eye, if the cornea be single, and the humours clear, the light will act correctly; but if there be a film over the cornea, or a cataract, or a skin between any of the humours, the rays of light will never make any impression on the internal seat of sight, the retina. ”

“ Many wholesome exercises could be devised to develop these several phases—judgments of distances, discrimination between different colors and different shades of the same color, the evaluation of light and shadow, the study of the æsthetic principles underlying the sense of proportion. An eye trained in this way would be a source of endless delight, a constant finder of new beauties. ”