As the quality of colours is discovered to the eye by the light, it is natural to conclude, that where there is most light, there also the true quality of the colour is to be seen; and where there is most shadow the colour will participate of, and be tinged with the colour of that shadow. Remember then to shew the true quality of the colour in the light parts only [56].
The colour which is between the light and the shadow will not be so beautiful as that which is in the full light. Therefore the chief beauty of colours will be found in the principal lights [57].
This is very observable in draperies, where the light folds casting a reflexion, and throwing a light on other folds opposite to them, make them appear in their natural colour. The same effect is produced by gold leaves casting their light reciprocally on each other. The effect is quite contrary if the light be received from an object of a different colour [58].
The colour of the shadows of an object can never be pure if the body which is opposed to these shadows be not of the same colour as that on which they are produced. For instance, if in a room, the walls of which are green, I place a figure clothed in blue, and receiving the light from another blue object, the light part of that figure will be of a beautiful blue, but the shadows of it will become dingy, and not like a true shade of that beautiful blue, because it will be corrupted by the reflexions from the green wall; and it would be still worse if the walls were of a darkish brown.
Colours placed in shadow will preserve more or less of their original beauty, as they are more or less immersed in the shade. But colours situated in a light space will shew their natural beauty in proportion to the brightness of that light. Some say, that there is as great variety in the colours of shadows, as in the colours of objects shaded by them. It may be answered, that colours placed in shadow will shew less variety amongst themselves as the shadows are darker. We shall soon convince ourselves of this truth, if, from a large square, we look through the open door of a church, where pictures, though enriched with a variety of colours, appear all clothed in darkness.
It is very possible that all the different colours may be changed into that of a general shadow; as is manifest in the darkness of a cloudy night, in which neither the shape nor colour of bodies is distinguished. Total darkness being nothing but a privation of the primitive and reflected lights, by which the form and colour of bodies are seen; it is evident, that the cause being removed the effect ceases, and the objects are entirely lost to the sight.
White is not a colour, but has the power of receiving all the other colours. When it is placed in a high situation in the country, all its shades are azure; according to the fourth proposition[59], which says, that the surface of any opake body participates of the colour of any other body sending the light to it. Therefore white being deprived of the light of the sun by the interposition of any other body, will remain white; if exposed to the sun on one side, and to the open air on the other, it will participate both of the colour of the sun and of the air. That side which is not opposed to the sun, will be shaded of the colour of the air. And if this white were not surrounded by green fields all the way to the horizon, nor could receive any light from that horizon, without doubt it would appear of one simple and uniform colour, viz. that of the air.
The light of the fire tinges every thing of a reddish yellow; but this will hardly appear evident, if we do not make the comparison with the daylight. Towards the close of the evening this is easily done; but more certainly after the morning twilight; and the difference will be clearly distinguished in a dark room, when a little glimpse of daylight strikes upon any part of the room, and there still remains a candle burning. Without such a trial the difference is hardly perceivable, particularly in those colours which have most similarity; such as white and yellow, light green and light blue; because the light which strikes the blue, being yellow, will naturally turn it green; as we have said in another place[60], that a mixture of blue and yellow produces green. And if to a green colour you add some yellow, it will make it of a more beautiful green.
The painter, who is to represent objects at some distance from the eye, ought merely to convey the idea of general undetermined masses, making choice, for that purpose, of cloudy weather, or towards the evening, and avoiding, as was said before, to mark the lights and shadows too strong on the extremities; because they would in that case appear like spots of difficult execution, and without grace. He ought to remember, that the shadows are never to be of such a quality, as to obliterate the proper colour, in which they originated; if the situation of the coloured body be not in total darkness. He ought to mark no outline, not to make the hair stringy, and not to touch with pure white, any but those things which in themselves are white; in short, the lightest touch upon any particular object ought to denote the beauty of its proper and natural colour.
The painter ought to know, that if any white object is placed between two walls, one of which is also white, and the other black, there will be found between the shady side of that object and the light side, a similar proportion to that of the two walls; and if that object be blue, the effect will be the same. Having therefore to paint this object, take some black, similar to that of the wall from which the reflexes come; and to proceed by a certain and scientific method, do as follows. When you paint the wall, take a small spoon to measure exactly the quantity of colour you mean to employ in mixing your tints; for instance, if you have put in the shading of this wall three spoonfuls of pure black, and one of white, you have, without any doubt, a mixture of a certain and precise quality. Now having painted one of the walls white, and the other dark, if you mean to place a blue object between them with shades suitable to that colour, place first on your pallet the light blue, such as you mean it to be, without any mixture of shade, and it will do for the lightest part of your object. After which take three spoonfuls of black, and one of this light blue, for your darkest shades. Then observe whether your object be round or square: if it be square, these two extreme tints of light and shade will be close to each other, cutting sharply at the angle; but if it be round, draw lines from the extremities of the walls to the centre of the object, and put the darkest shade between equal angles, where the lines intersect upon the superficies of it; then begin to make them lighter and lighter gradually to the point N O, lessening the strength of the shadows as much as that place participates of the light A D, and mixing that colour with the darkest shade A B, in the same proportion.
Blue and green are not simple colours in their nature, for blue is composed of light and darkness; such is the azure of the sky, viz. perfect black and perfect white. Green is composed of a simple and a mixed colour, being produced by blue and yellow.
Any object seen in a mirror, will participate of the colour of that body which serves as a mirror; and the mirror in its turn is tinged in part by the colour of the object it represents; they partake more or less of each other as the colour of the object seen is more or less strong than the colour of the mirror. That object will appear of the strongest and most lively colour in the mirror, which has the most affinity to the colour of the mirror itself.
Of coloured bodies, the purest white will be seen at the greatest distance, therefore the darker the colour, the less it will bear distance.
Of different bodies equal in whiteness, and in distance from the eye, that which is surrounded by the greatest darkness will appear the whitest; and on the contrary, that shadow will appear the darkest that has the brightest white round it.
Of different colours, equally perfect, that will appear most excellent, which is seen near its direct contrary. A pale colour against red, a black upon white (though neither the one nor the other are colours), blue near a yellow; green near red; because each colour is more distinctly seen, when opposed to its contrary, than to any other similar to it.
Any thing white seen in a dense air full of vapours, will appear larger than it is in reality.
The air, between the eye and the object seen, will change the colour of that object into its own; so will the azure of the air change the distant mountains into blue masses. Through a red glass every thing appears red; the light round the stars is dimmed by the darkness of the air, which fills the space between the eye and the planets.
The true colour of any object whatever will be seen in those parts which are not occupied by any kind of shade, and have not any gloss (if it be a polished surface).
I say, that white terminating abruptly upon a dark ground, will cause that part where it terminates to appear darker, and the white whiter.
Your window must be open to the sky, and the walls painted of a reddish colour. The summertime is the best, when the clouds conceal the sun, or else your walls on the south side of the room must be so high, as that the sun-beams cannot strike on the opposite side, in order that the reflexion of those beams may not destroy the shadows.
The window which gives light to a painting-room, ought to be made of oiled paper, without any cross bar, or projecting edge at the opening, or any sharp angle in the inside of the wall, but should be slanting by degrees the whole thickness of it; and the sides be painted black.
The shadows of any colour whatever must participate of that colour more or less, as it is nearer to, or more remote from the mass of shadows; and also in proportion to its distance from, or proximity to the mass of light.
To any white body receiving the light from the sun, or the air, the shadows should be of a blueish cast; because white is no colour, but a receiver of all colours; and as by the fourth proposition[61] we learn, that the surface of any object participates of the colours of other objects near it, it is evident that a white surface will participate of the colour of the air by which it is surrounded.
That shade will be the darkest which is produced by the whitest surface; this also will have a greater propensity to variety than any other surface; because white is not properly a colour, but a receiver of colours, and its surface will participate strongly of the colour of surrounding objects, but principally of black or any other dark colour, which being the most opposite to its nature, produces the most sensible difference between the shadows and the lights.
When one white body terminates on another of the same colour, the white of these two bodies will be either alike or not. If they be alike, that object which of the two is nearest to the eye, should be made a little darker than the other, upon the rounding of the outline; but if the object which serves as a ground to the other be not quite so white, the latter will detach of itself, without the help of any darker termination.
Of two objects equally light, one will appear less so if seen upon a whiter ground; and, on the contrary, it will appear a great deal lighter if upon a space of a darker shade. So flesh colour will appear pale upon a red ground, and a pale colour will appear redder upon a yellow ground. In short, colours will appear what they are not, according to the ground which surrounds them.
Amongst the figures which compose an historical picture, those which are meant to appear the nearest to the eye, must have the greatest force; according to the second proposition [62] of the third book, which says, that colour will be seen in the greatest perfection which has less air interposed between it and the eye of the beholder; and for that reason the shadows (by which we express the relievo of bodies) appear darker when near than when at a distance, being then deadened by the air which interposes. This does not happen to those shadows which are near the eye, where they will produce the greatest relievo when they are darkest.
Observe, that where the shadows end, there be always a kind of half-shadow to blend them with the lights. The shadow derived from any object will mix more with the light at its termination, in proportion as it is more distant from that object. But the colour of the shadow will never be simple: this is proved by the ninth proposition[63], which says, that the superficies of any object participates of the colours of other bodies, by which it is surrounded, although it were transparent, such as water, air, and the like: because the air receives its light from the sun, and darkness is produced by the privation of it. But as the air has no colour in itself any more than water, it receives all the colours that are between the object and the eye. The vapours mixing with the air in the lower regions near the earth, render it thick, and apt to reflect the sun’s rays on all sides, while the air above remains dark; and because light (that is, white) and darkness (that is, black), mixed together, compose the azure that becomes the colour of the sky, which is lighter or darker in proportion as the air is more or less mixed with damp vapours.
The shadows of bodies produced by the redness of the setting sun, will always be blueish. This is accounted for by the eleventh proposition[64], which says, that the superficies of any opake body participates of the colour of the object from which it receives the light; therefore the white wall being deprived entirely of colour, is tinged by the colour of those bodies from which it receives the light, which in this case are the sun and the sky. But because the sun is red towards the evening, and the sky is blue, the shadow on the wall not being enlightened by the sun, receives only the reflexion of the sky, and therefore will appear blue; and the rest of the wall, receiving light immediately from the sun, will participate of its red colour.
The colour of any object will appear more or less distinct in proportion to the extent of its surface. This proportion is proved, by observing that a face appears dark at a small distance, because, being composed of many small parts, it produces a great number of shadows; and the lights being the smallest part of it, are soonest lost to the sight, leaving only the shadows, which being in a greater quantity, the whole of the face appears dark, and the more so if that face has on the head, or at the back, something whiter.
Where the shadows terminate upon the lights, observe well what parts of them are lighter than the others, and where they are more or less softened and blended; but above all remember, that young people have no sharp shadings: their flesh is transparent, something like what we observe when we put our hand between the sun and eyes; it appears reddish, and of a transparent brightness. If you wish to know what kind of shadow will suit the flesh colour you are painting, place one of your fingers close to your picture, so as to cast a shadow upon it, and according as you wish it either lighter or darker, put it nearer or farther from it, and imitate it.
It happens very often that the shadows of an opake body do not retain the same colour as the lights. Sometimes they will be greenish, while the lights are reddish, although this opake body be all over of one uniform colour. This happens when the light falls upon the object (we will suppose from the East), and tinges that side with its own colour. In the West we will suppose another opake body of a colour different from the first, but receiving the same light. This last will reflect its colour towards the East, and strike the first with its rays on the opposite side, where they will be stopped, and remain with their full colour and brightness. We often see a white object with red lights, and the shades of a blueish cast; this we observe particularly in mountains covered with snow, at sun-set, when the effulgence of its rays makes the horizon appear all on fire.
Whatever object you intend to represent is to be supposed situated in a particular light, and that entirely of your own choosing. If you imagine such objects to be in the country, and the sun be overcast, they will be surrounded by a great quantity of general light. If the sun strikes upon those objects, then the shadows will be very dark, in proportion to the lights, and will be determined and sharp; the primitive as well as the secondary ones. These shadows will vary from the lights in colour, because on that side the object receives a reflected light hue from the azure of the air, which tinges that part; and this is particularly observable in white objects. That side which receives the light from the sun, participates also of the colour of that. This may be particularly observed in the evening, when the sun is setting between the clouds, which it reddens; those clouds being tinged with the colour of the body illuminating them, the red colour of the clouds, with that of the sun, casts a hue on those parts which receive the light from them. On the contrary, those parts which are not turned towards that side of the sky, remain of the colour of the air, so that the former and the latter are of two different colours. This we must not lose sight of, that, knowing the cause of those lights and shades, it be made apparent in the effect, or else the work will be false and absurd. But if a figure be situated within a house, and seen from without, such figure will have its shadows very soft; and if the beholder stands in the line of the light, it will acquire grace, and do credit to the painter, as it will have great relief in the lights, and soft and well-blended shadows, particularly in those parts where the inside of the room appears less obscure, because there the shadows are almost imperceptible: the cause of which we shall explain in its proper place.
Do not make the boundaries of your figures with any other colour than that of the back-ground, on which they are placed; that is, avoid making dark outlines.
The extremities of objects which are at some distance, are not seen so distinctly as if they were nearer. Therefore the painter ought to regulate the strength of his outlines, or extremities, according to the distance.
The boundaries which separate one body from another, are of the nature of mathematical lines, but not of real lines. The end of any colour is only the beginning of another, and it ought not to be called a line, for nothing interposes between them, except the termination of the one against the other, which being nothing in itself, cannot be perceivable; therefore the painter ought not to pronounce it in distant objects.
One of the principal parts of painting is the nature and quality of back-grounds, upon which the extremities of any convex or solid body will always detach and be distinguished in nature, though the colour of such objects, and that of the ground, be exactly the same. This happens, because the convex sides of solid bodies do not receive the light in the same manner with the ground, for such sides or extremities are often lighter or darker than the ground. But if such extremities were to be of the same colour as the ground, and in the same degree of light, they certainly could not be distinguished. Therefore such a choice in painting ought to be avoided by all intelligent and judicious painters; since the intention is to make the objects appear as it were out of the ground. The above case would produce the contrary effect, not only in painting, but also in objects of real relievo.
All solid bodies will appear to have a greater relief, and to come more out of the canvass, on a ground of an undetermined colour, with the greatest variety of lights and shades against the confines of such bodies (as will be demonstrated in its place), provided a proper diminution of lights in the white tints, and of darkness in the shades, be judiciously observed.
The back-grounds of any flat surfaces which are uniform in colour and quantity of light, will never appear separated from each other; vice versâ, they will appear separated if they are of different colours or lights.
The shadows or lights which surround figures, or any other objects, will help the more to detach them the more they differ from the objects; that is, if a dark colour does not terminate upon another dark colour, but upon a very different one; as white, or partaking of white, but lowered, and approximated to the dark shade.
No colour appears uniform and equal in all its parts unless it terminate on a ground of the same colour. This is very apparent when a black terminates on a white ground, where the contraste of colour gives more strength and richness to the extremities than to the middle.
What is fine is not always beautiful and good: I address this to such painters as are so attached to the beauty of colours, that they regret being obliged to give them almost imperceptible shadows, not considering the beautiful relief which figures acquire by a proper gradation and strength of shadows. Such persons may be compared to those speakers who in conversation make use of many fine words without meaning, which altogether scarcely form one good sentence.
If you mean that the proximity of one colour should give beauty to another that terminates near it, observe the rays of the sun in the composition of the rainbow, the colours of which are generated by the falling rain, when each drop in its descent takes every colour of that bow, as is demonstrated in its place [65].
If you mean to represent great darkness, it must be done by contrasting it with great light; on the contrary, if you want to produce great brightness, you must oppose to it a very dark shade: so a pale yellow will cause red to appear more beautiful than if opposed to a purple colour.
There is another rule, by observing which, though you do not increase the natural beauty of the colours, yet by bringing them together they may give additional grace to each other, as green placed near red, while the effect would be quite the reverse, if placed near blue.
Harmony and grace are also produced by a judicious arrangement of colours, such as blue with pale yellow or white, and the like; as will be noticed in its place.
Let the colours of which the draperies of your figures are composed, be such as to form a pleasing variety, to distinguish one from the other; and although, for the sake of harmony, they should be of the same nature[66], they must not stick together, but vary in point of light, according to the distance and interposition of the air between them. By the same rule, the outlines are to be more precise, or lost, in proportion to their distance or proximity.
All reflected colours are less brilliant and strong, than those which receive a direct light, in the same proportion as there is between the light of a body and the cause of that light.
An opake surface will partake most of the genuine colour of the body nearest to it, because a great quantity of the species of colour will be conveyed to it; whereas such colour would be broken and disturbed if coming from a more distant object.
Reflexes will partake, more or less, both of the colour of the object which produces them, and of the colour of that object on which they are produced, in proportion as this latter body is of a smoother or more polished surface, than that by which they are produced.
The surface of any opake body placed in shadow, will participate of the colour of any other object which reflects the light upon it. This is very evident; for if such bodies were deprived of light in the space between them and the other bodies, they could not shew either shape or colour. We shall conclude then, that if the opake body be yellow, and that which reflects the light blue, the part reflected will be green, because green is composed of blue and yellow.
No colour reflected upon the surface of another body, will tinge that surface with its own colour alone, but will be mixed by the concurrence of other colours also reflected on the same spot. Let us suppose A to be of a yellow colour, which is reflected on the convex C O E, and that the blue colour B be reflected on the same place. I say that a mixture of the blue and yellow colours will tinge the convex surface; and that, if the ground be white, it will produce a green reflexion, because it is proved that a mixture of blue and yellow produces a very fine green.
When two lights strike upon an opake body, they can vary only in two ways; either they are equal in strength, or they are not. If they be equal, they may still vary in two other ways, that is, by the equality or inequality of their brightness; they will be equal, if their distance be the same; and unequal, if it be otherwise. The object placed at an equal distance, between two equal lights, in point both of colour and brightness, may still be enlightened by them in two different ways, either equally on each side, or unequally. It will be equally enlightened by them, when the space which remains round the lights shall be equal in colour, in degree of shade, and in brightness. It will be unequally enlightened by them when the spaces happen to be of different degrees of darkness.
It happens very seldom that the reflexes are of the same colour with the body from which they proceed, or with that upon which they meet. To exemplify this, let the convex body D F G E be of a yellow colour, and the body B C, which reflects its colour on it, blue; the part of the convex surface which is struck by that reflected light, will take a green tinge, being B C, acted on by the natural light of the air, or the sun.
The lights upon the flesh colours, which are reflected by the light striking upon another flesh-coloured body, are redder and more lively than any other part of the human figure; and that happens according to the third proposition of the second book [67], which says, the surface of any opake body participates of the colour of the object which reflects the light, in proportion as it is near to or remote from it, and also in proportion to the size of it; because, being large, it prevents the variety of colours in smaller objects round it, from interfering with, and discomposing the principal colour, which is nearer. Nevertheless it does not prevent its participating more of the colour of a small object near it, than of a large one more remote. See the sixth proposition [68] of perspective, which says, that large objects may be situated at such a distance as to appear less than small ones that are near.
Black draperies will make the flesh of the human figure appear whiter than in reality it is [69]; and white draperies, on the contrary, will make it appear darker. Yellow will render it higher coloured, while red will make it pale.
Of all reflexions of the same shape, size, and strength, that will be more or less strong, which terminates on a ground more or less dark.
The surface of those bodies will partake most of the colour of the object that reflects it, which receive that reflexion by the most nearly equal angles.
Of the colours of objects reflected upon any opposite surface by equal angles, that will be the most distinct which has its reflecting ray the shortest.
Of all colours, reflected under equal angles, and at equal distance upon the opposite body, those will be the strongest, which come reflected by the lightest coloured body.
That object will reflect its own colour most precisely on the opposite object, which has not round it any colour that clashes with its own; and consequently that reflected colour will be most confused which takes its origin from a variety of bodies of different colours.
That colour which is nearest the opposed object, will tinge it the most strongly; and vice versâ: let the painter, therefore, in his reflexes on the human body, particularly on the flesh colour, mix some of the colour of the drapery which comes nearest to it; but not pronounce it too distinctly, if there be not good reason for it.
When, on account of some particular quality of the air, you can no longer distinguish the difference between the lights and shadows of objects, you may reject the perspective of shadows, and make use only of the linear perspective, and the diminution of colours, to lessen the knowledge of the objects opposed to the eye; and this, that is to say, the loss of the knowledge of the figure of each object, will make the same object appear more remote.
The eye can never arrive at a perfect knowledge of the interval between two objects variously distant, by means of the linear perspective alone, if not assisted by the perspective of colours.
The air will participate less of the azure of the sky, in proportion as it comes nearer to the horizon, as it is proved by the third and ninth proposition [70], that pure and subtile bodies (such as compose the air) will be less illuminated by the sun than those of thicker and grosser substance: and as it is certain that the air which is remote from the earth, is thinner than that which is near it, it will follow, that the latter will be more impregnated with the rays of the sun, which giving light at the same time to an infinity of atoms floating in this air, renders it more sensible to the eye. So that the air will appear lighter towards the horizon, and darker as well as bluer in looking up to the sky; because there is more of the thick air between our eyes and the horizon, than between our eyes and that part of the sky above our heads.
For instance: if the eye placed in P, looks through the air along the line P R, and then lowers itself a little along P S, the air will begin to appear a little whiter, because there is more of the thick air in this space than in the first. And if it be still removed lower, so as to look straight at the horizon, no more of that blue sky will be perceived which was observable along the first line P R, because there is a much greater quantity of thick air along the horizontal line P D, than along the oblique P S, or the perpendicular P R.
The natural colour of any visible object will be diminished in proportion to the density of any other substance which interposes between that object and the eye.
Let the colours vanish in proportion as the objects diminish in size, according to the distance.
The local colour of such objects as are darker than the air, will appear less dark as they are more remote; and, on the contrary, objects lighter than the air will lose their brightness in proportion to their distance from the eye. In general, all objects that are darker or lighter than the air, are discoloured by distance, which changes their quality, so that the lighter appears darker, and the darker lighter.
Local colours are entirely lost at a greater or less distance, according as the eye and the object are more or less elevated from the earth. This is proved by the seventh proposition [71], which says, the air is more or less pure, as it is near to, or remote from the earth. If the eye then, and the object are near the earth, the thickness of the air which interposes, will in a great measure confuse the colour of that object to the eye. But if the eye and the object are placed high above the earth, the air will disturb the natural colour of that object very little. In short, the various gradations of colour depend not only on the various distances, in which they may be lost; but also on the variety of lights, which change according to the different hours of the day, and the thickness or purity of the air, through which the colour of the object is conveyed to the eye.
Among several colours of the same nature, that which is the nearest to the eye will alter the least; because the air which interposes between the eye and the object seen, envelopes, in some measure, that object. If the air, which interposes, be in great quantity, the object seen will be strongly tinged with the colour of that air; but if the air be thin, then the view of that object, and its colour, will be very little obstructed.
Whatever be the colour of distant objects, the darkest, whether natural or accidental, will appear the most tinged with azure. By the natural darkness is meant the proper colour of the object; the accidental one is produced by the shadow of some other body.
The first part of any colour which is lost by the distance, is the gloss, being the smallest part of it, as a light within a light. The second that diminishes by being farther removed, is the light, because it is less in quantity than the shadow. The third is the principal shadows, nothing remaining at last but a kind of middling obscurity.
The azure of the sky is produced by the transparent body of the air, illumined by the sun, and interposed between the darkness of the expanse above, and the earth below. The air in itself has no quality of smell, taste, or colour, but is easily impregnated with the quality of other matter surrounding it; and will appear bluer in proportion to the darkness of the space behind it, as may be observed against the shady sides of mountains, which are darker than any other object. In this instance the air appears of the most beautiful azure, while on the other side that receives the light, it shews through that more of the natural colour of the mountain.
The same colour being placed at various distances and equal elevation, the force and effect of its colouring will be according to the proportion of the distance which there is from each of these colours to the eye. It is proved thus: let C B E D be one and the same colour. The first, E, is placed at two degrees of distance from the eye A; the second, B, shall be four degrees, the third, C, six degrees, and the fourth, D, eight degrees; as appears by the circles which terminate upon and intersect the line A R. Let us suppose that the space A R, S P, is one degree of thin air, and S P E T another degree of thicker air. It will follow, that the first colour, E, will pass to the eye through one degree of thick air, E S, and through another degree, S A, of thinner air. And B will send its colour to the eye in A, through two degrees of thick air, and through two others of the thinner sort. C will send it through three degrees of the thin, and three of the thick sort, while D goes through four degrees of the one, and four of the other. This demonstrates, that the gradation of colours is in proportion to their distance from the eye [72]. But this happens only to those colours which are on a level with the eye; as for those which happen to be at unequal elevations, we cannot observe the same rule, because they are in that case situated in different qualities of air, which alter and diminish these colours in various manners.