The landscape about us usually contains more of dark than of light (that is, as compared with the sky or its reflections from water, snow, or the like), and the inference I would draw from this is, that in ordinary landscape the lights hold stronger than the darks, because of the generally dark background against which they are shown. Reverse the ground, and the inference must likewise be reversed. Upon the mountain’s side the trunk of the white birch shows among the green pines like a strip of snow in an upper valley ; but place the birch and the pines upon the mountain’s ridge, where they are seen against a light sky, and immediately the pines show strongly and the birch is lost. Seen from the mountain’s top, looking down into the valley, a field of ripened grain surrounded by timber makes a light spot on the landscape ; but were the whole valley a mass of yellow grain, and one patch of timber stood in the middle of it, we can easily imagine the effect would be the direct opposite of what we at first noted.
Aside from colors showing as patches of light or dark on the landscape, the intervening atmosphere produces some’ changes in their hues which may be generally summarized by saying that as they recede in the distance the light colors be-come warmer and the dark colors lighter and sometimes colder. Thus at fifty yards a forest is filled with great patches of green, red, and warm brown ; but two miles away its foliage appears as a mass of purples, cold blues, and grays. The weather-beaten sail of a fishing-smack near at hand may be gray in color but out half a mile at sea or farther, especially at sunrise or sunset, it changes to a pale-orange tone not easily detected except by the trained eye of the painter. At two hundred yards distance purplish-red turns to orange-red, yellow becomes a warmer yellow bordering upon orange, ultramarine first turns to a purple and then quickly dissipates, and many of the lighter and more delicate hues are simply grayed down by the atmosphere into neutral tints.
I am not able to give you any scientific reason for these changes, nor state any positive law that will apply to all colors alike ; but the general rule of light colors becoming warmer, and dark colors lighter, and sometimes cooler, will answer our purposes, especially as we shall find its recognition among painters, so far as painters recognize any rules whatever. As a matter of fact there are few of them that know, or care to know, about theories of changing colors. Some of them paint nature just as they happen to see it, at times producing like the impressionists, violet shadows and blue lights ; others paint to make a picture, and if a certain color is wanted in a certain part of a picture to make tone or harmony, or for repetition’s sake, they put it there whether it is in nature or not. It is the prevailing belief that the painter is ever and always the most conscientious slave to the truths of nature, and so in the abstract he is but when he wishes to paint a picture he is first and last a slave to the truths of art. And rightly so. For it is not nature’s imitation we seek, but a painter’s impression of nature forcibly set forth through the medium of art.
Atmospheric effect upon lights and shadows is similar to that upon light or dark colors, a high light holding stronger among dark surroundings and a deep shadow holding stronger among light surroundings. When the contrast is not marked they both fade and finally disappear from view at about the same distance, and moreover, when in small quantities they generally disappear sooner than the objects reflecting them or causing them. In full sunlight a shadow is usually darker than the object casting it unless this object be black. The shadow of a tree, for instance, at noontime appears darker than the tree itself when close to view ; but when at a distance I think the shadow lightens and fades sooner than the dark of the tree, perhaps because its flat position does not enable it to be seen so well. When the shadows are in large masses there may be an exception to this, as there may be in regard to the lights. The deep shade on a mountain slope, or the sunlight on a white house, a tin roof, or a distant lake may be seen for miles, telling as distinct patches of dark or white on the landscape ; but the light on the trunk of a maple-tree will last little longer than the shadow back of it, and the varied play of light and shade among the leaves of that tree, easily seen near at hand, will be blurred out by distance, the lights about as quickly as the shades. After lines, colors, lights, and shades have all disapppeared, so far as our identification of them is concerned, there will still be a checkered or varied appearance about the objects possessing them. A mass of castellated rock upon the distant mountain’s side, long after its line and color are lost and the lights and shades of crevices and breaks have disappeared, will still not appear as one uniform hue. The mingling of color and light-and-shade will create variations in the tint which, though indefinable in their vagueness, are nevertheless apparent.
The. dissipating effect of atmosphere upon colors and intensities may be comprehended better if in our daily walks we take the opportunity of comparing like with like at different distances. There is, for instance, no commoner sight in cities than policemen dressed in blue coats standing on the street corners ; get two of them in a line of sight at the distances from you of, say, ten and one hundred yards, and you will immediately see the difference in the intensities of the blue. If the painter should not give this difference in pitch, but from mental knowledge perhaps, should represent the clothing of both policemen of the same intensity, the effect of distance and air would be destroyed, the two police-men would be inextricably pasted together, the first would not ” detach ” or stand apart from the second. If the policemen are not to be found in your walks of life, you may notice the effect of atmosphere on a row of elm or maple trees quite as readily. Get the trees in a line of sight, and notice first the difference in the tree-trunks. The one nearest you will be the darkest, or if not the darkest then the strongestthe most intense in color whatever its hueand as the trees recede they become lighter and weaker in a perfect ratio. The green of the trees will be affected in a similar way, fading away into gray-green and finally to gray-blue. The effect is noticeable even at short range if we look carefully, for though we cannot by taking thought or rubbing our eyes see a dry atmosphere a block away from us, yet we can very easily see its effect upon objects at that distance.
Atmosphere may seem at first thought a slight thing for the motive power of a picture because of its intangibility, its delicacy, its apparent remoteness from human interest ; but as it expresses a mood of nature, or a mood of the artist, I cannot see but that it is a beauty which, in connection with its usual attendants, tone and color, is pleasure-giving and worthy of serious consideration. In the early June mornings, when the light begins to flush along the tops of the eastern hills, there is a charm, a pleasure, a beauty in the feeling of cool air that fills the upper valleys ; in the pale mists that float along the hill-sides ; in the moist currents that move above the lowland meadows, blurring with invisible fingers the tall reeds and bushes, silvering over the foliage of the willows and poplars, and dripping dew into the cups of a thousand flowers. It was this early hour that Corot loved best the hour when he saw the beauty of the morning gleaming through a silver veil, and caught upon canvas the vision as it passed. At noon the mists and dews have gone, the trees stand motionless in the hot sun, casting heavy yet luminous shadows, butterflies of many hues waver about the nodding grass, and bees drone idly along from flower to flower, A warm air appears to rise from the earth, gathering around the maples on the walk, and occasionally lifting with its faint breath a single leaf. It hangs above the earth in waves of stillness like an enchanter’s spell, touching into immobility all warring elements of nature, and hushing for a time the contentions of men. This is the hour often chosen by those painters of nature’s brilliancy, Fortuny, De Nittis, Rico, and William M. Chase. And then comes twilight, when the trees stand up like silhouettes against the yellow sky, and the shadows come creeping down into the foreground. The pond is a motionless mirror of the sky ; the reeds and bushes are dull spots of brown or green ; the air moves hither and thither in faint gray waves pushing about little patches of mist already risen, imbuing all things with its spirit, and tinging all things with its hue. This was the hour of Daubignythe hour and the effect he so often depicted in his silver and golden landscapes along the banks of the Seine and the Marne.
Each clime has its peculiar atmosphere, the just painting of which gives local coloring and identity. At Scheveningen, looking up the beach to where the sand-dunes bend around in a horseshoe, we may see the heavy salt air of the sea wedged in the half-circle, just as we have often seen its counterpart in the pictures of the Dutch sea-painters. Off from the coast, receding out to sea, the orange-brown sails of the fishing- smacks are blown full of the same strong sea-wind ; the clouds go torn and flying across the upper sky, the waves come rolling in in great yellowish breakers that crash upon the beach just as Mesdag and others have portrayed them. Up over the protecting dykes the salt air carries far inland ; the clouds drift over towns, woods and meadows ; and the gray and damp of the ocean, like human breath upon glass, change the whole scene into a color-tone of pearly-gray such as you may have noticed in the landscapes of Mauve or Willem Maris. In Cairo, down the long narrow street at noonday, the hot air looks half-blue, half-red, as though the stones of the street were furnaces driving off iridescent heat which quavers and rocks itself skyward. The roofs and the walls glare white in the sun. Dark flat shadows are thrown across the street in which, crouched against the buildings, sit white-hooded figures. A gayly-trapped donkey staggers with his load. In the distance looms like a shaft of light the white minaret of a mosque. Overhead is the deep-blue of the Egyptian sky. It was thus that Decamps and Fromentin saw and painted the beauty of the East. Here, in New Jersey, there are days in June when the air is thick with moisture ; dull leaden clouds go slowly voyaging along the sky ; the heavy foliage is saturated with rain ; the meadows are half obscured in mist ; the hills are altogether lost. Graygray atmospherecreeps into every nook and breathes its moist breath upon every object, until the ruling spirit of the scene is saturation. It is thus that Mr. Inness, our own landscape painter, has portrayed it.
The history of aerial perspective, as practised among the painters, may be briefly told. I cannot say positively who began the use of it, for any artist that I might name would be sure to have a forerunner who practised it somewhat. I can only point to a period when all the artists of a school began to interest themselves in it. We have no reason to sup-pose that any of the Pre-Renaissance artists knew very much about it. The knowledge of it among the Italians was extensive, as shown by the writings of Leonardo, but neither he nor his contemporaries demonstrated it any too successfully in landscape work. Their foregrounds were green or brown, their backgrounds were blue, and little gradation appeared between these two extremes. Their handling of it in figure compositions was much better, though by no means remarkable. Correggio and the Venetians improved upon the Florentines in aerial perspective, as they did in all things relating to the technic of painting except drawing and composition ; but I do not know that any one of them made atmosphere a picture motive. In Spain, Velasquez was its master, and painted it with wonderful effect, as the celebrated picture of the ” Tapestry Weavers” will show. But it was the Dutch and Flemish schools that first put it forward as a peculiar beauty of a picture, as may be seen in those interiors of Pieter de Hooghe and Jan van der Meer of Delft, of which I have spoken ; in the architectural pieces of Van der Heyden, in the landscapes of Hobbema and Wynants, in the marines of Van de Velde, and in the figure pieces of Rem brandt.
In France, during the first quarter of this century, atmosphere and, in fact, all natural effects had been largely abandoned for the beauty of the classic and the academic ; but about the beginning of the second quarter of the century it was again brought into notice by Constable and Bonington, and more forcibly and poetically by Corot and the Orientalists, Fromentin and Decamps. The Fontainebleau-Barbizon school all understood it and painted it with the most poetic results, especially men like Troyon, Jacque, Rousseau, Daubigny and Millet. Among the moderns there are so many painters devoted to it that I can mention but a few of them : Lerolle, Cazin, Besnard, Monet, in France ; Weir, Twachtman, Tryon, Robinson, in America ; and Israels, Mauve, Willem Maris, and others, in Holland.
As I have intimated, some of the moderns go to extremes in the portrayal of atmosphere, filling a room with something that may be seen almost as readily as smoke, blurring figures out of all recognition at ten paces, because there happen to be other figures at five paces, and stopping up the end of a hundred-yard street with an impenetrable scumble of gray paint in lieu of air. Such work may be clever in its way as exemplifying values, and artists may sometimes speak of such pictures as ” stunning things,” but they ” stun ” more by their falsity than their truth. The scumble is at the best a questionable means of obtaining aerial effects at short range ; for a dry atmosphere that can be seen at a hundred yards is generally too apparent to be true. We need not, however, find fault with the painter’s methods if they but render the right effects and when we consider with what slight tools he produces these effects of naturea brush, a few colors, and a flat surfaceperhaps we should not find fault with him at all.