The transfer, either drawn in line or in chalk, or from a plate, being obtained, it is next transferred to a polished litho stone. Of course, the picture can be at once transferred to the zinc which it is intended to etch, but it will be found best to first of all transfer to stone, then from the stone pull a transfer, and transfer that to the zinc, so that in case of an accident during the etching another plate can be quickly prepared. Before placing them upon the stone, the prepared transfers should lie in a damping book until evenly damp.
Now take a polished litho stone and place it in front of a fire or in the sun until it is quite dry, then place it upon the bed of the press, and adjust the pressure; then place the transfer upon the stone in such a manner that it lies without any slurring. Next place a piece of clean paper upon the transfer, then the blanket, lower the tympan, run in the carriage, lower the lever, and pull through; then lift the lever, draw back the carriage, turn the stone round and pull through again, then sponge the back of the transfer with water and pull through again, repeating the damping, and pulling through three or four times. Now with a wet sponge saturate the back of the transfer with water, and lift away the paper, then wash away the composition, leaving the image on the stone; now cover it with thick gum solution, and allow it to dry.
If more than one transfer is in hand at a time, they are trimmed as closely as possible and pasted with very thin paste close together upon a large piece of paper, and then all can be transferred at one operation.
The gum upon the stone being dry, wash it off carefully with clean water, then roll up with transfer ink. Clean away any dirt there may be with sponge and snake stone; where the snake stone cannot be used, a piece of pointed wood, dipped into acid gum, will clear way the dirt. Take care to have the wet sponge handy so as to prevent the acid spreading upon the work; now roll up as strong as possible, then etch, by passing over water acidulated with nitric acid of such a strength that it just slightly effervesces when the stone is touched; saturate a sponge with the weak acidulated water and go gently over the stone, then with another sponge charged with clean water, wash off the acid. Now again roll up with transfer ink as strong as possible, and pull the transfer. Chalk drawings are transferred to stone in the same way, then etched, but the acid water is allowed to act a little longer than for a line transfer, and after {54} washing away the etching solution, the picture is washed out with clean turpentine, then wiped with a sponge, gummed in, fanned dry, moistened with a wet sponge, and the water removed. Then the image is rolled up with transfer ink, and the transfers pulled for subsequent etching.
To transfer to zinc, take a piece of polished zinc and immerse it in the graining bath (page [40]) for about a minute; then remove it, wash it under the tap, and rub it with soft sponge; then wipe it dry with a soft rag, and warm the plate slightly; lay it upon a litho stone in the press, lay the transfer (which has been lying in the damping book) upon the zinc plate; lay upon the transfer the piece of blanket, lower the tympan and pull through; then damp the back of the transfer, pull it through again; then reverse the plate, dampen the back of the transfer, pull through again; again dampen the back of the transfer, and again pull through; now saturate the transfer with water, peel off the paper, remove the composition, and apply with a sponge a sufficiency of a solution of gum (thickness of cream), 5 ounces; decoction of nutgalls, 10 ounces. The decoction of nutgalls is made as directed on page [56.]
Allow this to stay on the zinc for about a minute, then wash off, cover with plain gum, fan dry, and dip a sponge in gum and rub over the plate; now dip a soft rag into the gum, then into the etching ink (page [57]) mixed with a little cocoanut oil or mutton fat and middle varnish, continuing the application of gum and ink until the whole of the picture is sharp, black, and strong. Be sure and keep the plate well covered with gum and the ink as thick as possible.
The plate is now dusted with finely powdered resin, sponged with a wet sponge, and then is placed in the etching trough containing water and just sufficient nitric acid to taste; in this the plate remains about half a minute, rocking the etching trough gently all the time; now remove the plate, wash it under the tap, rubbing gently back and front with a sponge, then dry by gentle heat; next coat the back, edges, and margin and portions of the front which are too large to etch away, with thin shellac varnish. When dry proceed to etch as directed in the next chapter.
Instead of inking up with the rag after etching with the acid gum, wash off, then roll up with a leather roller charged with the etching ink mixed with a little cocoanut oil, and used as stiff as it is possible to work it, until the image has taken in all possible, damping the zinc with a sponge directly it shows any signs of getting dry; then dampen slightly, and repeat as above. Next immerse it in the etching bath as before; wash well, and dry; coat the back, edges and margin on the front with shellac varnish, when the plate will be ready for etching.
CHAPTER VIII. ETCHING LINE TRANSFERS.
For etching transfers on zinc, whether photographic or direct, we shall require the following apparatus: A slab of iron about 24 × 18 inches and 1⁄2 or 1 inch thick, supported horizontally upon four legs, and heated by an atmospheric burner, arranged somewhat like a gridiron so that the heat is even all over. A set of rollers on litho stock, one of leather, one of flannel, and one or two glazed rollers, the same as lithographers use for tint printing—we also require an etching box—i. e., a wooden tray, 30 × 24 inches, and 8 inches deep, well made of seasoned wood, lined with either pitch (with a little tallow added), or gutta-percha, and mounted upon rockers.