(c) Transfers from relief plates made in copper, steel, zinc, or lead (music).
(d) Anastatic transfers.
(e) Fat or resin prints from photographic negatives.
Proceed as follows:
(a) Transfer of hand-drawing.—Place the drawing to be transferred with its face upon a sheet of clean, white paper, and moisten the back with a weak solution of nitric acid (1⁄2° Baumé), by means of a sponge. Over-moistening causes obliteration of the drawing, fringing of the single lines, and the running together of the hatched portions. The correct degree of moisture can be ascertained when the side prepared and drawn upon grows slightly sticky, and when the drawing becomes glossy. This will take place in from four to five minutes after moistening. This time is to be spent in arranging the zinc in the press, after having freed it from all greasiness. Place a card on the rolling press below the drawing and the zinc; above it, a sheet of good blotting-paper, a sheet of Bristol paper and are of pressing board; then make a trial print with the press, a clean piece of paper taking the place of the drawing. The correct pressure is a matter of experience; it is advisable to begin with a pressure less by one sheet, in order to be able to increase it during the process of transfer.
In the lithographic press the ink-block is first to be adjusted; since it needs a greater “setting in” than the rolling press, the zinc must be cut larger. It must extend three centimetres on all sides beyond the drawing. The edges of the cut plate must be well ground off, in order that the ink-block may not be {74} caught; at all events, it is advisable to have the latter smaller than the plate. Observe that the range of the press should be regulated; then place the zinc directly, without any intervening layer of paper, on a solid stone; lay upon it a clean sheet of paper, a blotter, a sheet of Bristol paper, and a pressing board well covered with tallow. Make a trial by drawing the sheet through at a moderate pressure. If all is arranged, the work of transfer can be started. The temperature of the zinc should now be about 35° C.
Place the drawing down carefully, without moving it about; upon it the blotter, the Bristol paper, and a pressing board, and draw it through three times with constantly increasing pressure; turn the plate in a contrary direction, and draw it through three times in the same manner. Now place a moistened sheet of good paper between the blotter and the drawing, and draw through, first with weak, and then with strong pressure, three times in both positions. Instead of turning the zinc, the ink-block may be reversed. This finishes the operation of transprinting, and the next question is the loosening of the paper from the zinc. Here we can pursue two methods: first, we can have hot water and a porcelain tray at hand; place the copied plate in the tray, and pour the water upon it. The coated layer bearing the drawing begins to separate from the paper. Shaking the tray promotes this action, and soon the paper will loosen itself from the layer which remains attached to the zinc. With the second method proceed thus: moisten the back of the copied drawing, thoroughly with a sponge and cold water; allow it to soak in, warm the plate to 60°–65° C. and carefully rub all parts by hand. The layer will again separate by degrees from the paper, which latter we can then easily lift off from the plate.
On account of the strongly gelatinous layer, crayons on grained paper should only be moistened moderately before and after the first rolling, in order to avoid the coiling of the paper.
Hand-drawings on paper without coloring require treatment with stronger acid (I recommend nitric acid, 4° Beaumé). At the same time the drawing should be cut as close as possible. To draw it through securely, place it as usual upon the zinc, and above it a piece of prepared copy paper moderately moistened, and a trifle larger than the drawing, then a blotter, a Bristol board, and a thick card, and draw through as before. The coated copy paper sticks tight to the zinc after the first rolling; it also retains the drawing in its first position, and allows repeated rolling. If the original was over-moist when {75} copying, it sticks to the zinc and separates with difficulty; if the moistening was just right, two perfect copies can often be made from the same original.
I have attempted to copy drawings on a fatty zinc surface, and to etch them strongly, but, far from being satisfied with the result, I prefer the above method.