Читать книгу A Treatise on Etching - Maxime Lalanne - Страница 4

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As explained in the Preface, this chapter has been added to enable the beginner to master the most necessary technical elements of etching, without complicating his first attempts by artistic considerations. Let him learn how to use his ground, his points, and his acid, before he endeavors to employ these requisites in the production of a work of art.

All the materials and tools necessary for making the experiment described below can be bought at the following places:[A]—

New York: Henry Leidel, Artist's Materials, 341 Fourth Avenue.

Philadelphia: Janentzky & Co., Artist's Materials, 1125 Chestnut Street.

Boston: J. H. Daniels, Printer, 223 Washington Street.

But any one living within reach of a druggist, a paint-shop, and a hardware-store can do just as well with the exercise of a little patience and a very little ingenuity. For the benefit of such persons all the necessary directions will be given for making what it may be impossible to buy.

[A] In London, Mr. Hamerton recommends Mr. Charles Roberson, 99 Long Acre.

1. Definition of Etching.—To be able to get an impression on paper from a metal plate in a copper-plate printing-press, it is necessary to sink the lines of the design below the surface of the plate, so that each line is represented by a furrow. The plate is then inked all over, care being taken to fill each furrow, and finally the ink is cautiously wiped away from the surface, while the furrows are left charged with it. A piece of moist paper pressed against a plate so prepared, will take the ink up out of the furrows. The result is an impression. In engraving proper these furrows are cut into the plate by mechanical means; in etching chemical means are used for the same purpose. If nitric acid is brought into contact with copper, the acid corrodes the metal and finally eats it up altogether; if it is brought into contact with wax or resinous substances, no action ensues. Hence, if we cover a copper plate with a ground or varnish composed of wax and resinous substances, and then draw lines upon this ground with a steel or iron style or point, so that each stroke of the point lays bare the copper, we shall have a drawing in lines of copper (which are affected by nitric acid) on a ground of varnish (which is not thus affected). If now we expose the plate to the action of nitric acid for a certain length of time, we shall find, upon the removal of the ground by means of benzine, that the lines have been bitten into the plate, so that each line forms a furrow capable of taking up the ink. The depth and the breadth of the lines depends upon the thickness of the points used, and upon the length of time allowed for biting; or, in other words, by varying the size of the points and the time of exposure the lines may also be made to vary. This is the whole of the science of etching in a nutshell.

2. Requisites.—The following tools and materials are the only ones which are absolutely necessary for a first experiment:—

1. A Copper Plate on which to execute your etching. Do not waste your money on a large plate. A visiting-card plate is sufficiently large. If you happen to have an engraved plate of that kind, you can use the back of it. If you have none, get one at a card-engraver's. The price ought not to be over fifteen cents. If you do not live in any of the large cities named above, or cannot find a card-engraver, send fifteen cents in stamps to Mr. Geo. B. Sharp, 45 Gold St., New York, N. Y., who will forward a plate to you by mail. Be very particular in giving your full and correct post-office address. These plates only need cleaning to fit them for use.

2. Benzine, used for cleaning the plate, sold by grocers or druggists at about five cents a pint for common quality.

3. Whiting or Spanish White, also for cleaning the plate. A very small quantity will do.

4. Clean Cotton Rags.—Some pieces of soft old shirting are just the thing.

5. Etching-Ground, with which to protect the plate against the action of the acid. This ground is sold in balls about the size of a walnut. If you do not live in a city where you can buy the ground, you may as well make it yourself. Here is a recipe for a very cheap and at the same time very good ground. It is the ground used by Mr. Peter Moran, one of the most experienced of our American etchers. Buy at a drug-shop (not an apothecary's) or painter's supply-store:—

Two ounces best natural asphaltum (also called Egyptian asphaltum), worth about ten cents.

One and a half ounces best white virgin wax, worth about six cents.

One ounce Burgundy pitch, worth say five cents.

Break the wax into small pieces, and reduce the Burgundy pitch to fine powder in a mortar, or have it powdered at the drug-shop. Take a clean earthenware pot glazed on the inside, with a handle to it (in Boston you can buy one for fifteen cents at G. A. Miller & Co.'s, 101 Shawmut Avenue), and in this pot melt your asphaltum over a slow fire, taking very good care not to let it boil over, or otherwise you might possibly set the house afire. When the asphaltum has melted add the wax gradually, stirring all the while with a clean glass or metal rod. Then add the Burgundy pitch in the same way. Keep stirring the fluid mass, and let it boil up two or three times, always taking care to prevent boiling over! Then pour the whole into a pan full of tepid water, and while it is still soft and pliant, form into balls of the required size, working all the while under the water. If you touch the mass while it is still too hot, you may possibly burn your fingers, but a true enthusiast does not care for such small things. You will thus get about eight or nine balls of very good ground at an outlay of about thirty-six cents in cash, and some little time. Nearly all recipes order the wax to be melted first, but as the asphaltum requires a greater heat to reduce it to a fluid condition, it is best to commence with the least tractable substance. For use, wrap a ball of the ground in a piece of fine and close silk (taffeta), and tie this together with a string.

6. Means of heating the Plate.—Any source of heat emitting no smoke will do, such as a kitchen stove, a spirit lamp, or a small quantity of alcohol poured on a plate and ignited (when the time arrives).

7. A Hand Vice with a wooden handle, for holding the plate while heating it; price about seventy-five cents at the hardware-stores. But a small monkey-wrench will do as well, and for this experiment you can even get along with a pair of pincers.

8. A Dabber for laying the ground on the plate. Cut a piece of stout card-board, two or three inches in diameter; on this lay a bunch of horse-hair, freed from all dust, and over this again some cotton wool. Cover the whole with one or two pieces of clean taffeta (a clean piece of an old silk dress will do), draw them together tightly over the card-board, and tie with a string. When finished the thing will look something like a lady's toilet-ball. The horse-hair is not absolutely necessary, and may be omitted.

9. Means of Smoking the Ground.—The ground when laid on the plate with the dabber, is quite transparent and allows the glitter of the metal to shine through. To obtain a better working surface the ground is blackened by smoking it. For this purpose the thin wax-tapers known to Germans as “Wachsstock,” generally sold at German toy-stores, are the best. They come in balls. Cut the tapers into lengths, and twist six of them together. In default of these tapers, roll a piece of cotton cloth into a roll about as thick and as long as your middle finger, and soak one end of it in common lamp or sperm oil.

10. Stopping-out Varnish, used for protecting the back and the edges of the plate, and for “stopping out,” of which more hereafter. If you cannot buy it you can make it by dissolving an ounce of asphaltum, the same as that used for the ground, in about an ounce and a half of spirits of turpentine. Add the asphaltum to the turpentine little by little; shake the bottle containing the mixture frequently; keep it in the sun or a moderately warm place. The operation will require several days. The solution when finished should be of the consistency of thick honey.

11. Camel's-Hair Brushes, two or three of different sizes, for laying on the stopping-out varnish, and for other purposes.

12. Etching Points or Needles, for scratching the lines into the ground. Rat-tail files of good quality, costing about twenty cents each at the hardware-stores, are excellent for the purpose. Two are all you need for your experiment, and even one will be sufficient. Still cheaper points can be made of sewing, knitting, or any other kind of needles, mounted in sticks of wood like the lead of a lead-pencil. Use glue or sealing-wax to fasten them in the wood.

13. An Oil-Stone for grinding the points.

14. An Etching-Tray to hold the acid during the operation of biting. Trays are made of glass, porcelain, or india-rubber, and can generally be had at the photographer's supply-stores. A small india-rubber tray, large enough for your experiment, measuring four by five inches, costs fifty-five cents. But you can make an excellent tray yourself of paper. Make a box, of the required size and about one and a half inches high, of pasteboard, covered over by several layers of strong paper, well glued on. If you can manage to make a lip or spout in one of the corners, so much the better. After the glue has well dried pour stopping-out varnish into the box, and float it all over the bottom and the sides; pour the residue of the varnish back into your bottle, and allow the varnish in the box to dry; then paint the outside of the box with the same varnish. Repeat this process three or four times. Such a tray, with an occasional fresh coating of varnish, will last forever. For your experiment, however, any small porcelain (not earthenware) or glass dish will do, if it is only large enough to hold your plate, and allow the acid to stand over it to the height of about half an inch.

15. A Plate-Lifter, to lift your plate into and out of the bath without soiling your fingers. It consists of two pieces of string, each say twelve to fifteen inches long, tied to two cross-pieces of wood, each about six inches long, thus . It is well to keep the fingers out of the acid, as it causes yellow spots on the skin, which remain till they wear off.

16. Nitric Acid for biting in the lines. Any nitric acid sold by druggists will do, but the best is the so-called chemically pure nitric acid made by Messrs. Powers & Weightman, of Philadelphia. It comes put up in glass-stoppered bottles, the smallest of which hold one pound, and sell for about sixty cents.

17. Water for mixing with the acid and for washing the plate.

18. Blotting-Paper, soft and thick, several sheets, to dry the plate, as will be seen hereafter.

19. Spirits of Hartshorn or Volatile Alkali.—This is not needed for etching, but it is well to have it at hand, in case you should spatter your clothes with acid. Spots produced by the acid can generally be removed by rubbing with the alkali, which neutralizes the acid.

3. Grounding the Plate.—Having procured all these requisites, the first thing to do will be to clean the plate so as to remove any oil or other impurities that may have been left on it by the plate-maker. Wash and rub it well on both sides with a soft cotton rag and benzine, and then rub with whiting, as you would do if you were to clean a door-plate. Take care to remove all the whiting with a clean rag. Now take hold of your plate by one of its corners with the hand-vice, wrench, or pincers, between the jaws of which you have put a bit of card-board or stout paper, so as not to mark the plate. Hold it over the stove, spirit lamp, or ignited alcohol, and see to it that it is heated evenly throughout. Hold the plate in your left hand while heating it, and with the other press against it the ball of ground wrapped up in silk. As soon as you see the ground melting through the silk, distribute it over the plate by rubbing the ball all over its surface (the polished surface, as a matter of course), taking care the while that the plate remains just hot enough to melt the ground. If it is too hot, the ground will commence to boil and will finally burn. The bubbles caused by boiling are liable to leave air-holes in the ground through which the acid may bite little holes in the plate; burning ruins the ground altogether, so that it loses its power of withstanding the acid. After you have distributed the ground tolerably evenly, and in a thin layer, lay the plate down on the table (keeping hold of it, however, by the corner), and finish the distribution of the ground by dabbing with the dabber. Strike the plate quickly and with some force at first, and treat it more gently as the ground begins to cool. If it should have cooled too much, before the distribution is accomplished to your satisfaction, in which case the dabber will draw threads, heat the plate gently. The dabber not only equalizes the distribution of the varnish, but also removes what is superfluous. An extremely thin layer of ground is sufficient.

4. Smoking the Plate.—While the plate is yet hot, and the ground soft, it must be smoked. Light your tapers or your oil torch, and turn the plate upside down. Allow the flame just to touch the plate, and keep moving it about rapidly, so that it may touch all points of the plate, without remaining long at any one of them. If this precaution is ignored, the ground will be burned, with the result before stated. The smoking is finished as soon as the plate is uniformly blackened all over, and the glimmer of the metal can no longer be seen through the ground. Now allow the plate to cool so that the ground may harden. Avoid dust as much as possible while grounding and smoking the plate. Particles of dust embedded in the ground may cause holes which will admit the acid where you do not wish it to act.

5. Points or Needles.—The plate is now ready for drawing upon it, but before you can proceed to draw you must prepare your points or needles. Two will do for this first experiment, a fine one and a coarse one. For the fine one you may use a sewing-needle, for the coarser one a medium embroidery needle, both set in wood so that the points project about a quarter of an inch. If you are going to use rat-tail files, grind the handle-ends on your oil-stone until they attain the requisite fineness. Hold the file flat on the stone, so as to get a gradually tapering point, and turn continually. See to it that even the point of your finest needle is not too sharp. If it scratches when you draw it lightly over a piece of card-board, describe circles with it on the board until it simply makes a mark without scratching. The coarse needle must be evenly rounded, as otherwise it may have a cutting point somewhere.