With a clear atmosphere an illusion of opening distance may be secured with the far distance and the greater part of the middle distance unobservable, but in such a case a successful design is difficult to accomplish owing to the limited number of signs available. Many signs, as trees and houses, either darken or hide the view, while sunlight effects on unobstructed ground, sufficiently definite to be used as signs, could not be very numerous without appearing abnormal. The only really first-class method of producing a satisfactory near-ground illusion was invented by Hobbema in the later years of his life. This is to use skilfully placed trees and other signs through which paths wind, or appear to wind, and to throw in a strong sunlight from the back.[a] The light enables far more signs to be used in depth than would otherwise be possible, and so the eye has a comparatively long track to follow. That the remarkable beauty of the pictures of Hobbema composed in this way is almost entirely due to the illusion thus created, is readily seen when they are compared with some of his other works, very similar in all respects except that the light is thrown in from the front or the side. Before placing his light at the back, the artist tried the side plan in many pictures, and while this was a decided improvement upon his earlier efforts to secure depth of near-ground signs, it was naturally inferior to the latest scheme. Jacob Ruysdael adopted the plan of Hobbema in two or three works with great effect.[]
When the middle distance is hidden by a rising foreground, an illusion may be created by the far distance alone if this be of considerable depth. Since the fifteenth century it has been a frequent practice to conceal the middle distance, though mostly in pictures of figure subjects.[64] The Dutch artists of the seventeenth century who painted open-air scenes of human and animal life, as Paul Potter, Wouverman, and Albert Cuyp, avoided the middle distance whenever possible, but often managed to secure a fair illusion. In pure landscape the system is less often practised, and never by great artists.
The only means available to the painter of land views for creating an illusion of motion, apart from that of opening distance, is by the representation of flowing water so that a series of successive events in the flow, each connected with, but varying in character from, the preceding one, can be exhibited. Thus, a volume of water from a fall proceeds rapidly over a flat surface to a ledge, and thence perhaps to another ledge of a different depth, from which it passes over or round irregular rocks and boulders, and thence over smaller stones or into a stream, creating in its passage every kind of eddy and current.[c] Here is a series of progressive natural actions in which the progression is regular and continuous, while the separate actions cover such time and space that they may be readily separated by the eye. If, therefore, the whole series be properly represented, an illusion of motion will result.[65] Obviously the canvas must be of considerable size, and the breaks in the flow of water as varied in character and as numerous as possible. Everdingen and Jacob Ruysdael seem to have been the first artists to recognize the significance of this progression, but Ruysdael far surpassed his master in the exhibition of it. He examined the problem in all its variations, solved it in a hundred ways, and at his death left little for succeeding painters to learn regarding it. Very rarely, one meets with a landscape where the double illusion of motion of water and opening distance is provided, and needless to say the effect is superb.[d]
Sea views occupy a position by themselves inasmuch as there is a fixed horizontal distance for the artist. He cannot shorten this depth without making his work look abnormal, and an effort to increase it by presuming that the picture is painted from a considerable height above the sea level, is seldom successful because the observer of the work finds a difficulty in fitting in the novelty with his experience. Except when depicting stormy weather, or showing a thick atmosphere, the painter of a sea view has no trouble in obtaining absolute accuracy in his linear perspective, but this is not sufficient, for if a variety of trees, herbage, brooks, and so on, requires an illusion of movement, then certainly does a sea view which has monotony for its keynote. The motion of the waves in fine weather cannot be suggested on canvas because it is continuous and equal. One wave displaces another and so far as the eye can reach there is only a succession of similar waves. Thus the motion appears unbroken, and from the canvas point of view the waves must be motionless as the sand hillocks of a desert. Of course in the actual view, the expanse, the "immeasurable stretch of ocean," is impressive and to some extent weird, but nothing of this feeling is induced by a painted miniature. With a bright sky and clear atmosphere the painter of a sea view cannot well obtain an illusion of opening distance by means of a multiplication of signs as on land, for the introduction of many vessels would give the work a formal appearance, but the problem can be satisfactorily solved by putting the sun in the sky towards the setting, and using cloud shadows as signs. Aivasovsky, one of the greatest marine painters of modern times, was very successful with this class of work. His long shadows thrown at right angles to the line of sight, carry back the distance till the horizon seems to be further off than experience warrants, the illusion being perfect. An illusion of opening distance may, however, be easily obtained in a sea view when there is a haze covering, but not hiding, the horizon, by introducing as signs, two or three vessels, the first in the middle distance.
Another method of giving a suggestion of motion, which may be used by the sea painter, is in truthfully representing the appearance of the water round a vessel passing through it. What is probably the finest example of this work in existence is Jacob Ruysdael's The Rising Storm.[e] The sea is shown close to a port, and half a dozen smacks and small boats are being tossed about by choppy, breaking waves. In the centre of the picture is a large smack over the weather bow of which a huge foaming wave has broken, and part is spending its force on the lee bow, from which the water gradually becomes quieter till at the stern of the boat little more than a black concavity is seen. The progression of wave movement is completely represented, and the effect is very impressive.
The coast painter can produce an excellent illusion of motion from waves breaking on a beach, for in nature this action is made up of a series of different consecutive acts each of which is easily distinguishable to the eye. The wave rises, bends over its top which becomes crested, and splashes forward on the beach, to be converted into foam which races onwards, breaking up as it goes till it reaches the watermark, then rapidly falling back to be met by another wave. Here is a series of consecutive incidents which can all be painted so as to deceive for a moment with the idea of motion. The attempt to represent the action of waves breaking against steep rocks is invariably a failure, because of the great reduction of the apparent number of incidents forming the consecutive series. In nature the eye is not quick enough to follow the separate events, and so they cannot be distinguished in a painting. Thomson's fine picture of Fast Castle is distinctly marred by a wide irregular column of water shown splashing up against a rock. There is no possibility here of representing a series of actions, and so an instant suffices to fix the water on the rock. In another work by the same artist there are waves breaking against precipitous rocks, but in this case the water first passes over an expanse of low lying rocks, and a sequence of actions is shown right up to the cliff, an excellent illusion of movement being brought about.[f]
Apart from those exhibiting an illusion of motion of some kind, the only landscapes which have a permanent value, are near-ground scenes in which conditions of atmosphere of common experience, as rain or storm are faithfully rendered. In these works the signs must be numerous and varied in character, for it is only in the multiplication of small changes of form and tone that the natural effects of a particular weather condition can be imitated. Jacob Ruysdael and Constable were the greatest masters of this form of landscape, Crome and Boecklin closely approaching them, but it is uncommon for a serious worker in landscape to attempt a picture where distance is not recorded. The best paintings of Constable present an illusion of opening distance, and when Jacob Ruysdael painted near-ground only, it was nearly always a hilly slope with water breaking over low rocks.
Moonlight and twilight scenes are not good subjects for the painter of landscape, because, shown as they must be in daylight, or with artificial light, they become distinctly uninteresting after the first impression of tonal harmony has passed away, owing to the unconscious revolt of the mind against something with an unreal appearance.[66] This is the chief reason why no scene has lived which depended for its beauty entirely upon moonlight effects. It is about two hundred and fifty years since Van der Neer died, and he still remains practically the only moonlight painter known to us whose works seem of permanent interest. But he did not rely altogether upon moonlight effects for his beauty, for the representation of distance is the principal feature in all his works. Further he commonly makes us acquainted with the human life and habitations of his time, and in this way enhances our appreciation of his pictures. Before Van der Neer, moonlight scenes were very rarely executed, and only two or three of these have remained which are worthy of serious consideration. The best of them is a view by Rubens, where the light is comparatively strong, and practically the whole of the beauty rests in the opening distance, which can hardly be surpassed in a work of this kind.[g]
It is not necessary to deal with varieties of pure landscape other than those mentioned. They are painted in their myriads, and form pleasant tonal harmonies, or have local interest, but they do not live. As the foliage in springtime they are fresh and welcome to the eye when they first appear, but all too soon they fade and disappear from memory like the leaves of the autumn.
In landscape as in all other branches of painting, whatever is ephemeral in nature, or of uncommon experience, should be avoided. Rare sun effects and exceptional phases of atmosphere should not find their way into pictures, while strokes of lightning and rainbows should only be present when they are necessitated by the design, and then must be subordinated as far as possible. Of all these things the most strongly to be deprecated are strange sunlight effects, for they have the double drawback for the painter, of rarity and evanescence in nature. A stroke of lightning is not out of place where the conditions may be presumed to be more or less permanent, as in the celebrated picture of Apelles, where Alexander was represented in the character of Jupiter casting a thunderbolt, and forks of lightning proceed from his hand; or where the occurrence is essential in the composition, as in Gilbert's Slaying of Job's Sheep.[h] So in Danby's The Sixth Seal Opened, the lightning is quite appropriate, for all nature is disturbed. In Martin's Plague of Hail, and The Destruction of Pharaoh, the first a night scene, and the second a view darkened by dense black clouds, lightning is well used for lighting purposes; and in Cot's The Storm,[] where the background is dark and no sky is visible, lightning is the only means possessed by the artist of explaining that the fear expressed by the lovers in the foreground, arises from the approaching storm. Great masters like Giorgione,[j] Rubens,[k] Poussin,[l] used a stroke of lightning on rare occasions, but took every care that it should not be conspicuous, or interfere in any way with the first view of the picture. The lightning is invariably placed in the far background, and no light is apparently reflected from it.