A Treatise on Etching Part 4

25. =Precautions to be observed while Drawing.=--Before you begin to draw you must trace the margin of your design, for the guidance of the printer. To protect your plate, it will be necessary to cover it with very soft paper; the pressure of the hand does no harm, provided you avoid rubbing the varnish. If you should happen to damage it, you must close up the brilliant little dots which you will observe, by touching them up, very lightly and with a very fine brush, with stopping-out varnish.

26. =Directions for Drawing with the Needle.=--I might now let you copy some very simple etching; but your knowledge of drawing will, I believe, enable you to try your hand at a somewhat more important exercise. Let us suppose, then, that you are to draw a landscape, although the practice you are about to acquire applies to all other subjects equally well. Will you reproduce this design by Claude Lorrain? (Pl. II.) It is a composition full of charm and color, and very harmonious in effect.

Use only one needle, and keep your work close together in the distance and more open in the foreground. (See Pl. I^_a_.) That appears paradoxical to you; but the nitric acid will soon tell you why this is so. I shall indicate to you, after your plate has been bitten, those cases in which you will have to proceed differently, or, in other words, in which you will have to draw your lines nearer together or farther apart without regard to the different distances. I cannot explain this subject more fully before you have become acquainted with the process of biting in, as without this knowledge it must remain unintelligible to you. This remark holds good, also, of what I have told you on the subject of the needles of different degrees of sharpness.

"It is curious, my dear sir, to notice how at one and the same time the point combines a certain degree of softness and of precision; those who draw with the pen ought also to be admirers of etching. It seems to me, however, that my lines are too thick; I have already laid several of them, and the varnish is no longer visible; I am afraid I have taken it up altogether."

You need not feel any uneasiness about that; it is simply owing to the irradiation of the copper, the brilliancy of which the screen does not completely subdue. The bright line is made to look broader than it really is by the brilliant gloss of the metal. But if you lay a piece of tracing-paper on the plate you will see the lines as they really are; that is to say, with plenty of s.p.a.ce between them. By the aid of a lens you can convince yourself still more easily; you will often have occasion to avail yourself of this instrument to enable you to do fine work with greater facility, or to give you a better insight into what you have already done.

As the irradiation of which we have just spoken is apt to deceive us in regard to the quant.i.ty of the work done, we may happen to find less of it than we expected when the plate has been bitten. Plates which to the beginner seem to be quite elaborately worked, present to the acid lines widely s.p.a.ced and insufficient in number, thus necessitating retouches.

It is essential, therefore, in principle (except in the special cases to be pointed out hereafter), to give to our work, in its first stages, all the development that is necessary.

I forgot to tell you that you must provide yourself with a very soft brush, say a badger, which, from time to time, you must pa.s.s lightly over your plate so as to remove the small particles of varnish raised by the needle. Otherwise you will not be able to see properly what you have been doing.

Continue, and follow your own feeling; work away without fear of going wrong; some of your errors you will be able to remedy. Thus, if you have made a mistake, you can lay a thin coat of liquid varnish over the spoiled part by means of a brush; in a few seconds the varnish will have dried, and you can make your correction. You can employ this method for the correction of a faulty line, or to restore a place which should have remained white, but which you have inadvertently shaded.

Here I shall stop for the present, and shall close by saying, May good luck attend your point, as well as your acid! There is nothing more to be said to you until after your plate has been bitten.

CHAPTER III.

BITING.

27. =Bordering the Plate.=--This work took some time. Our young student, impatient to see the transformation wrought by the acid, came back without keeping me waiting for him.

"Hurry up! A tray, acid, and all the accessories!"

Instead of using a tray, I tell him, we can avail ourselves of another method, which is used by many engravers, and which consists in bordering the plate with wax. This wax,[6] having been softened in warm water, is flattened out into long strips, and is fastened hermetically and vertically around the edges of the plate, so that, when hardened, it forms the walls of a vessel, the bottom of which is represented by the design drawn with the point. To avoid dangerous leaks, heat a key, and pa.s.s it along the wax where it adheres to the plate; the wax melts, and, on rehardening, offers all possible guarantees of solidity. We now pour the acid on the plate thus converted into a tray, and as we have taken care to form a lip in one of the angles made by the bordering wax, it is an easy matter to pour off the liquid after each biting. This proceeding is useful in the case of plates which are too large for the tray.

Otherwise, however, I prefer a tray made of gutta-percha or porcelain.

28. =The Tray.=--Let us now install ourselves at this table, and let us cover the margin and the back of the plate with a thick coat of stopping-out varnish. As soon as the varnish is perfectly dry, we place the plate into the tray standing horizontally on the table, and pour on acid enough to cover it to the height of about a centimetre. This depth, which is sufficient for biting, allows the eye to follow the process in its various stages.

29. =Strength of the Acid.=--This acid is fresh, and has not yet been used; bought at forty degrees, I mix it with an equal quant.i.ty of water, which reduces it to twenty degrees. This is the strength generally adopted for ordinary biting. Its color is clear, and slightly yellow; but as soon as it takes up the copper it becomes blue, and then green. As, in its present state, it would act too impetuously, I add to it a small quant.i.ty of acid which has been used before. You may also throw a few sc.r.a.ps of copper into it the day before using it; the old etchers used for this purpose a copper coin, larger or smaller, according to the volume of the bath.[7]

30. =Label your Bottles!=--One day, one of my pupils, having a bad cold, did not notice the difference between the smell of the acid and that of the turpentine, and so plunged a plate which he desired to bite, into a bath of the latter fluid. "It's queer," he said, "this won't bite, and yet the varnish scales off.... The lines keep enlarging, and run into one another! What does this curious medley mean, which appears on the plate?" It was simple enough. The spirits of turpentine had dissolved the ground, and consequently the plate developed a shining and radiating surface before the eyes of our wondering student, as if it had just left the hands of the plate-maker.

Advice to those who are absent-minded, and who are liable to mistake fluids which look alike for one another,--Label your bottles!

31. =The First Biting.=--Let us make haste now, I say to my pupil, to do our biting. As the heat of the day abates, the acid becomes less active; and besides, to judge by the delicate character of the original we are to render, we shall need at least two or three hours, all told, for this operation. The task before us consists in the reproduction of a given work, the merit of which lies in the gradation in the various distances.

It needs time and attention to be able to carry all the necessary processes successfully into practice.

It will be plain to you, from what I have just said, that the operation you are about to engage in is one of the most delicate in the etcher's practice. There is the plate in the acid; the liquid has taken hold of the copper; but your sky must be light, and a prolonged corrosion would therefore be hurtful to it. Hence we take the plate out of the bath, pa.s.s it through pure water, so that no acid is left in the lines, and cover it with several sheets of blotting-paper, which, being pressed against it by the hand, dries the plate. We shall have to go through the same process after each partial biting, because if the plate were moist, the stopping-out varnish which we are going to apply to it would not adhere.

32. =The Use of the Feather.=--You noticed the lively ebullitions on the plate, which took place twice in succession. After the first, I pa.s.sed this feather lightly over the copper, to show you its use. Its vane removed the bubbles which adhered to the lines. This precaution is necessary, especially when the ebullitions acquire some intensity and are prolonged, to facilitate the biting, as the gas by which the bubbles are formed keeps the acid out of the lines. If these bubbles are not destroyed, the absence of biting in the lines is shown in the proofs by a series of little white points. Such points are noticeable in some of the plates etched by Perelle, who, it seems, ignored this precaution.

33. =Stopping Out.=--The two rapid ebullitions which you saw may serve you as a standard of measurement; the biting produced by them must be very light, and sufficient for the tone of the sky. You may, therefore, cover the entire sky with stopping-out varnish by means of a brush, taking care to stop short just this side of the outlines of the other distances. The importance of mixing lamp-black with your stopping-out varnish to thicken it, comes in just here; because if it remained in its liquid state, it might be drawn by capillary attraction into the lines of those parts which you desire to reserve, and thus, by obstructing them, might stop the biting in places where it ought to continue. Wait till the varnish has become perfectly dry; you can a.s.sure yourself of this by breathing upon it; if it remains brilliant, it is still soft, and the acid will eat into it; but as soon as it is dry it will a.s.sume a dull surface under your breath.[8]

34. =Effect of Temperature on Biting.=--Let us now return the plate to the bath, to obtain the values of the other distances. The temperature has a great effect on the intensity of the ebullitions, and it is hardly possible to depend on it absolutely as a fixed basis on which to rest a calculation of the time necessary for each biting, as its own variability renders it difficult to appreciate the aid to be received from it. In winter, for instance, with the same strength of acid, it needs four or five times as much time to reach the same result as in summer, so that on very hot days the biting progresses so rapidly that the plate cannot be lost sight of for a single moment without risk of over-biting.

[Ill.u.s.tration: Pl. I_a_.]

35. =Biting continued.=--We have now obtained several moderate ebullitions, and as it would not do to exaggerate the tone of the mountain in the background, it is time to withdraw the plate once more.

Uncover a single line by removing the ground, either with the nail of your finger or with a very small brush dipped into spirits of turpentine, to examine whether it is deeply enough bitten for the distance which it is to represent. If the depth is not sufficient, cover it with stopping-out varnish, and bite again. This is not necessary, however, in our present case, and you may therefore stop out the whole background. Remember, if you please, that the line must look _less_ heavy than it is to show in the proof; for you must take into account the black color of the printing-ink. With your brush go over the edges of the trees which are to be relieved rather lightly against the sky, as well as over that part of the shadow in this tower which blends with the light. There are also some delicate pa.s.sages in the figure of the woman in the foreground, in the details of the plants, and in the folds of this tent (Pl. I_a_). Stop out all these, and do not lose sight of the values of the original (Pl. II.). Make use of the brush to revarnish several places which are scaling off on the margin and the back of the plate. The temperature is favorable; the ebullitions come on without letting us wait long, and the plate is bluing rapidly. I do not like to see these operations drag on; in winter, therefore, I do my biting near the fire. We soon acquire a pa.s.sion for biting, and take an ever-growing interest in it, which is incessantly sharpened by thinking of the result to which we aspire. Hence the desire of constant observation, and that a.s.siduity in following all the phases of the biting-in.

I notice that the acid does not act on certain parts of your work; you will find out soon enough what that means.

36. =Treatment of the Various Distances.=--"I am thinking just now of what you told me in regard to the background:--that more work ought to be put into it than into the foreground."

Nothing, indeed, is simpler. You understand that the background, which is bitten in quite lightly, must show very delicate lines, while in the middle distance and in the foreground the lines are enlarged by the action of successive bitings. When it comes to the printing, the quant.i.ty of ink received by these various lines will be in proportion to the values which you desired to obtain, and in the proofs you will have a variety of lighter or stronger tones, giving you the needed gradations in the various distances. It follows from this that, if you had worked too sparingly on the distances which receive only a light biting, you could not have reached the value of the tone which you strove to get, and if you had worked too closely on those parts which require continued biting, you would have had a black and indistinct tone, because the lines, which are enlarged by the acid, and consequently keep approaching one another, would finally have run together into one confused ma.s.s, producing what in French is called a _creve_ (blotch).

In an etching the s.p.a.ce between the lines must be made to serve a purpose; for the paper seen between the black strokes gives delicacy, lightness, and transparency of tone.

37. =The Creve.--Its Advantages and Disadvantages.=--In very skilled hands the _creve_ is a means of effect. If you wish to obtain great depth in a group of trees, in a wall, in very deep shadows, you will risk nothing by intermingling your lines picturesquely and biting them vigorously. In this way you can produce tones of velvety softness, and at the same time of extraordinary vigor. Similarly, you may strike a fine note by means of running together several lines which, if sufficiently bitten, will form but a single broad one of great solidity and power. It is, indeed, only the exaggeration of this expedient, which, by unduly enlarging the limits of the broad line just spoken of, and thus producing a large and deep surface between them, const.i.tutes the _creve_ properly so called; the printing ink has no hold in this flat hollow, and a gray spot in the proof is the result. I have warned you of the accident; later on you shall hear something of the remedy. We will now continue our biting. Plunge your plate into the bath again, if you please.

38. =Means of ascertaining the Depth of the Lines.=--"My dear sir, I see that my drawing turns black; it disappears almost entirely, and is lost in the color of the ground.[9] I am quite perplexed. My mind endeavors to penetrate beneath this varnish, so as to be able to witness the mysterious birth of my _oeuvre_. See these violent ebullitions! What do you think of them?"

Let them go on a moment longer, and then withdraw your plate. We have now arrived at a point where the eye cannot judge of the work of the acid as easily as before; henceforth we must, therefore, examine the depth of our bitings by uncovering a single line, as, for instance, this one here in the ground. Or we may even lay bare, by the aid of spirits of turpentine, a part of the foreground, provided, however, that we must not forget to cover it again with the brush. This will give us an idea of the total effect so far produced by the biting, and we can then regulate the partial bitings which are still to follow, either by a comparison of the time employed on those that have gone before, or by the intensity of the ebullitions, the action of which on the copper we have already studied. You perceive that, while it is difficult to fix a standard of time for the bitings at the beginning of the operation, it is yet possible to calculate those to come by what we have so far done.

39. =The Rules which govern the Biting are subordinated to various Causes.=--In reality, it is impossible to establish fixed rules for the biting, for the following reasons:--

1. Owing to the varying intensity of the stroke of the needle. The etcher who confines himself to gently baring his copper must bite longer than he who attacks his plate more vigorously, and therefore exposes it more to the action of the acid.

2. Owing to the different quality of the plates.

3. Owing to the difference in temperature of the surrounding air:--of this we have before spoken.

4. Owing to difference of strength in the acid, as it is impossible always to have it of absolutely the same number of degrees. At 15 to 18 the biting is gentle and slow; at 20 it is moderate; at 22 to 24 it becomes more rapid. It would be dangerous to employ a still higher degree for the complete biting-in of a plate, especially in the lighter parts.

40. =Strong Acid and Weak Acid.=--It is, nevertheless, possible to put such strong acid to good service. A fine gray tint may, for instance, be imparted to a well-worked sky by pa.s.sing a broad brush over it, charged with acid at 40. But the operation must be performed with lightning speed, and the plate must instantly be plunged into pure water.

As a corollary of the fourth cause, it is well to know that an acid overcharged with copper loses much of its force, although it remains at the same degree. Thus an acid taken at 20, but heavily charged with copper from having been used, will be found to be materially enfeebled, and to bite more slowly than fresh acid at 15 to 18. To continue to use it in this condition would be dangerous, because there is no longer any affinity between the liquid and the copper, and if, under such circ.u.mstances, you were to trust to the appearance of biting (which would be interminable, besides), you would find, on removing the varnish, that the plate had merely lost its polish where the lines ought to be, without having been bitten. It is best, therefore, always to do your biting with fresh acid, constantly renewed, as the results will be more equal, and you will become habituated to certain fixed conditions.

Some engravers, of impetuous spirit and impatient of results, do their biting with acid of a high degree, while others, more prudent, prefer slow biting, which eats into the copper uniformly and regularly, and hence they employ a lower degree. In this way the varnish remains intact, and there is not that risk of losing the purity of line which always attends the employment of a stronger acid.

41. =Strength of Acid in relation to certain Kinds of Work.=--Experience has also shown that, with the same proportion in the time employed, the values are accentuated more quickly and more completely by a strong than by a mild acid; this manifests itself at the confluence of the lines, where the acid would play mischief if the limit of time were overstepped.

Another effect of biting which follows from the preceding, is noticeable in lines drawn far apart. Of isolated lines the acid takes hold very slowly, and they may therefore be executed with a cutting point and bitten in with tolerably strong acid.

The reverse takes place when the lines are drawn very closely together; the biting is very lively. Work of this kind, therefore, demands a needle of moderate sharpness and a mild acid.

Hence, interweaving lines and very close lines are bitten more deeply by the same acid than lines drawn parallel to each other, and widely s.p.a.ced, although they may all have been executed with the same needle.

If, in an architectural subject, you have drawn the lines with the same instrument, but far apart on one side, and closely and crossing each other on the other, you must not let them all bite the same length of time, if you wish them to hold the same distance. It will be necessary to stop out the latter before the former, otherwise you will have a discordant difference in tone. There will be inequality in the biting, but it will not be perceptible to the eye, as the general harmony has been preserved. (See Pl. IV. Fig. 1.)

In short, strong acid rather widens than deepens the lines; mild acid, on the contrary, eats into the depth of the copper, and produces lines which are shown in relief on the paper, and are astonishingly powerful in color. This is especially noticeable in the etchings of Piranesi, who used hard varnish.

42. =Last Stages of Biting.=--But let us return to our operation. You noticed that I allowed your plate to bite quite a while; this was necessary to detach your foreground and middle-ground vigorously from the sky and the background. You may now stop out the trees, the tower, and the tent in the middle-ground, and the vertical part of the bridge, which is in half-tint, and then proceed. Note that the number of bitings is not fixed, but depends on the effect to be reached.