CHAPTER XII

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_Of LIGHT and SHADE, and the manner in which objects are explained to the eye by them_.

Although both this and the next chapter may seem more particularly relative to the art of painting, than any of the foregoing; yet, as hitherto, I have endeavour'd to be understood by every reader, so here also I shall avoid, as much as the subject will permit, speaking of what would only be well-conceived by painters.

There is such a subtile variety in the nature of appearances, that probably we shall not be able to gain much ground by this enquiry, unless we exert and apply the full use of every sense, that will convey to us any information concerning them.

So far as we have already gone, the sense of feeling, as well as that of seeing, hath been apply'd to; so that perhaps a man born blind, may, by his better touch than is common to those who have their sight, together with the regular process that has been here given of lines, so feel out the nature of forms, as to make a tolerable judgment of what is beautiful to sight.

Here again our other senses must assist us, notwithstanding in this chapter we shall be more confined to what is communicated to the eye by rays of light; and tho' things must now be consider'd as appearances only; produced and made out merely by means of _lights, shades,_ and _colours_.

By the various circumstances of which, every one knows we have represented on the flat surface of the looking-glass, pictures equal to the originals reflected by it. The painter too, by proper dispositions of lights, shades, and colours, on his canvas, will raise the like ideas. Even prints, by means of lights and shades alone, will perfectly inform the eye of every shape and distance whatsoever, in which even lines must be consider'd as narrow parts of shade, a number of them, drawn or engrav'd neatly side by side, called _hatching_, serve as shades in prints, and when they are artfully managed, are a kind of pleasing _succedaneum_ to the delicacy of nature's.

Could mezzo-tinto prints be wrought as accurately as those with the graver, they would come nearest to nature, because they are done without strokes or lines.

I have often thought that a landskip, in the process of this way of representing it, doth a little resemble the first coming on of day. The copper-plate it is done upon, when the artist first takes it into hand, is wrought all over with an edg'd-tool, so as to make it print one even black, like night: and his whole work after this, is merely introducing the lights into it; which he does by scraping off the rough grain according to his design, artfully smoothing it most where light is most required: but as he proceeds in burnishing the lights, and clearing up the shades, he is obliged to take off frequent impressions to prove the progress of the work, so that each proof appears like the different times of a foggy morning, till one becomes so finish'd as to be distinct and clear enough to imitate a day-light piece. I have given this description because I think the whole operation, in the simplest manner, shews what lights and shades alone will do.

As light must always be supposed, I need only speak of such privations of it as are called shades or shadows, wherein I shall endeavour to point out and regularly describe a certain order and arrangement in their appearance, in which order we may conceive different kinds of softnings and modulations of the rays of light which are said to fall upon the eye from every object it sees, and to cause those more or less-pleasing vibrations of the optic nerves, which serve to inform the mind concerning every different shape or figure that presents itself.

The best light for seeing the shadows of objects truly, is, that which comes in at a common sized window, where the sun doth not shine; I shall therefore speak of their order as seen by this kind of light: and shall take the liberty in the present and following chapter, to consider colours but as variegated shades, which together with common shades, will now be divided into two general parts or branches.

The first we shall call PRIME TINTS, by which is meant any colour or colours on the surfaces of objects; and the use we shall make of these different hues will be to consider them as shades to one another. Thus gold is a shade to silver, &c. exclusive of those additional shades which may be made in any degree by the privation of light.

The second branch may be called RETIRING SHADES, which gradate or go off by degrees, as figs. [84 and 85 T p. II]. These shades, as they vary more or less, produce beauty, whether they are occasioned by the privation of light, or made by the pencilings of art or nature.

[Illustration: Figs. 84 and 85]

When I come to treat of colouring, I shall particularly shew in what manner the gradating of prime tints serve to the making a beautiful complexion; in this place we shall only observe how nature hath by these gradating shades ornamented the surfaces of animals; fish generally have this kind of shade from their backs downward; birds have their feathers enriched with it; and many flowers, particularly the rose, shew it by the gradually-increasing colours of their leaves.

The sky always gradates one way or other, and the rising or setting sun exhibits it in great perfection, the imitating of which was Claud. de Loraine's peculiar excellence, and is now Mr. Lambert's: there is so much of what is called harmony to the eye to be produced by this shade, that I believe we may venture to say, in art it is the painter's gamut, which nature has sweetly pointed out to us in what we call the eyes of a peacock's tail: and the nicest needle-workers are taught to weave it into every flower and leaf, right or wrong, as if it was as constantly to be observed as it is seen in flames of fire; because it is always found to entertain the eye. There is a sort of needle-work called Irish-stitch, done in these shades only; which pleases still, tho' it has long been out of fashion.

There is so strict an analogy between shade and sound, that they may well serve to illustrate each other's qualities: for as sounds gradually decreasing and increasing give the idea of progression from, or to the ear, just so do retiring shades shew progression, by figuring it to the eye. Thus, as by objects growing still fainter, we judge of distances in prospects, so by the decreasing noise of thunder, we form the idea of its moving further from us. And with regard to their similitude in beauty, like as the gradating shade pleases the eye, so the increasing, or swelling note, delights the ear.

I have call'd it the retiring shade, because by the successive, or continual change in its appearance, it is equally instrumental with converging lines[13], in shewing how much objects, or any parts of them, retire or recede from the eye; without which, a floor, or horizontal-plane, would often seem to stand upright like a wall. And notwithstanding all the other ways by which we learn to know at what distances things are from us, frequent deceptions happen to the eye on account of deficiencies in this shade: for if the light chances to be so disposed on objects as not to give this shade its true gradating appearance, not only spaces are confounded, but round things appear flat, and flat ones round.

[13] See p. 17. The two converging lines from the ship, to the point C, under fig. 47, plate I.

[Illustration: Fig. 94]

But although the retiring shade hath this property, when seen with converging lines, yet if it describes no particular form, as none of those do in fig. 94, on top of plate II, it can only appear as a flat-pencil'd shade; but being inclosed within some known boundary or out-line, such as may signify a wall, a road, a globe, or any other form in perspective where the parts retire, it will then shew its retiring quality: as for example, the retiring shade on the floor, in plate II, which gradates from the dog's feet to those of the dancer's, shews, that by this means a level appearance is given to the ground: so when a cube is put into true perspective on paper, with lines only, which do but barely hint the directions every face of it is meant to take, these shades make them seem to retire just as the perspective lines direct; thus mutually compleating the idea of those recessions which neither of them alone could do.

[Illustration: gradated shade]

Moreover, the out-line of a globe is but a circle on the paper; yet, according to the manner of filling up the space within it, with this shade, it may be made to appear either flat, globular, or concave, in any of its positions with the eye; and as each manner of filling up the circle for those purposes must be very different, it evidently shews the necessity of distinguishing this shade into as many species or kinds, as there are classes or species of lines, with which they may have a correspondence.

In doing which, it will be found, that, by their correspondency with, and conformity to objects, either composed of straight, curved, waving, or serpentine lines, they of course take such appearances of variety as are adequate to the variety made by those lines; and by this conformity of shades we have the same ideas of any of the objects composed of the above lines in their front aspects, as we have of them by their profiles; which otherwise could not be without feeling them.

Now instead of giving engraved examples of each species of shade, as I have done of lines, I have found that they may be more satisfactorily pointed out and described by having recourse to the life.

But in order to the better and more precisely fixing upon what may be there seen, as the distinct species, of which all the shades of the retiring kind in nature partake, in some degree or other, the following scheme is offered, and intended as an additional means of making such simple impressions in the mind, as may be thought adequate to the four species of lines described in