THE colour of distant landscape varies in a thousand ways, according to the conditions under which it is seen. In Italy, for instance, a distance may be supremely blue, while in England it may be a varied commingling of tender greys. In this country the distance often merges into the sky, so that it is impossible to see the line which marks the actual division. In Scotland, on a clear autumn evening, when looking towards the sun, the distant hills are often of a simple tone of deep purple ; but with the low light of the setting sun shining upon them, every detail of the variegated cultivation, scraps of rock or patches of heather, etc., are revealed. We know how distant these objects are in Nature, but how to realise that sense of distance when painted in this high key of colour is a most difficult problem. We know that certain objects in Nature are at such-and-such a distance from us, and our knowledge of the fact prevents us from depending upon the sense of judgment by colour. We do a mental sum in miles instead of making a close study, as we should do, of the difference of colour values. The diminution of form is resorted to before we begin to think of the difference in colour. This arises from the fact that it is so easy to judge the size of a known object, such as a house or figure, and from that we almost unconsciously express our opinion. I say "almost," since it is not always the case, for we frequently hear the exclamation from someone who gazes from a height, " How small the people look !" This is an example of the constant appeal to scale as a proof of distance. The road winding through a valley, a row of poplar trees, or distant houses are tangible. They diminish in form as they recede, at the same rate under all atmospheric conditions. But what shall we say of colour which is governed by conditions of atmosphere in its wonderful changes from dawn to sunset ? Not for an hour is the colour at any given distance the same. Almost imperceptibly it changes in sympathy with the sky, and vouchsafes fresh revelations of character as the general volume of light increases and wanes through the long summer day. Observe the shadow which started with a long line down the hillside, creeping on till it hides itself behind the brightening trees, and throws itself like a blue-purple line across the winding road. The cottages, which were dark before, are now white as marble patches on the sapphire background of the sky. The river, which wound below the hill in modest grey, now flashes back the burnished gold of mid-day, whilst the sun marches triumphantly on its course, each step adding a new beauty in place of each departing charm. The glamour of heat makes the distance magical. It vibrates and scintillates through and over all things, and gives mysterious changes to the scene we saw hours ago in the young light of the morning. It fills the landscape with a glistening flood of reflection. Every leaf in the foreground which holds its face upwards laughs back to the glory of the sunshine, and the far-sweeping distance throbs in its strange effulgence. There are no shadows visible now, except from the near objects, as the sun is high above us, and the whole of the distance is bathed in light. We are struck by the breadth and beauty of illumination, but to convey the sensation by our painted canvas is an end more easily desired than attained.
One should notice the colour effect of this heat glamour, in its multitudinous variations. The artist should absorb it into his memory, for it is infinitely more beautiful than we deemed possible.
I know of no master of the old school who has attempted to conquer this problem. I know of few pictures in Europe which, since landscape painting became an independent art, have adequately expressed the wonder of it. Yet it is evident, to the observant eye, almost every summer day ; it is, perhaps, one of its most familiar effects. It is known to all, yet painted by few. I would not counsel any student of landscape painting to attempt it at first, particularly in its influence on distant colour, until he has overcome the less formidable effects. Let him select an effect when the shadows reveal the modelling of the trees, or lay their grey veils over hill or road. He will find it hard enough in all conscience without essaying the most difficult. Distance under any conditions is sufficiently baffling. It is a subject that demands, yet repays, the most diligent study. A beautiful distance which leads the eye through and beyond the taint of a landscape, is one of the charms which unfailingly appeals to the lover of Nature and Art.
I will endeavour to furnish you with a few hints that may be profitable and instructive. Let us imagine a landscape comprising trees and a grass foreground, across which a path winds over the ridge of a field in the middle distance. Stretching among its undulations, a river skirts the sloping field and is then hidden by intercepting trees or the elevation of its bank. At the back, the grass fields and ploughed lands recede towards the sky line. We know that grass afar off is green ; it is composed of the same material as the grass at our feet, and the natural inclination is, of course, to judge the colour by our knowledge of this familiar fact. But let us take a test case. Here is a hillock close to our feet. If we lower our face, so as to bring the grass of the foreground on a level with the grass lands of the distance, we find our conception of the colour of the latter completely upset. It is a grey, and not green, and of such a quality as to suggest the distance between them. Between the two colours thus juxtaposed lie all the variations of tone that inter- vene between the nearest material and the more remote. The nearest grass is the positive green of its local colour. The colour of the distant grass may be obtained by white, cobalt, yellow ochre, a touch of rose madder and raw umber ; and when seen through a haze (an effect so difficult to paint), you will find that yellow ochre, cobalt, and the least suspicion of rose madder (all suppressed, of course, with white) will approach the tone. But only experience can tell the exact proportions of each colour suitable for the purpose. The lower sky must be painted at the same time as the extreme distance. You may have observed that these are nearly the same, the alteration of texture and treatment being all that is necessary to suggest the difference.