Now take a glue roller (the same as used for inking up the albumen image on zinc, described in Part I., Chapter IV.), and having spread a little of the ink described in the last chapter (chalk, litho. ink, and mutton fat) upon the slab, charge the roller carefully with a thin coating of ink, and then, having {138} removed any moisture from the face of the transfer with a soft sponge, apply the inked glue roller, rolling one way only—i.e., from the body (presuming that the edge of paper tucked under the slab is next the body of the operator); continue rolling until the whole of the lines forming the picture are coated with ink, and the whites quite clean and free from ink. If the roller should get wet from water oozing from under the transfer, wipe it with a damp cloth and then roll it a few times on the inking slab, and continue rolling the transfer. Be careful that the portion of the transfer representing the whites of the picture has absorbed its full modicum of water before beginning to roll up, and also that there is not too much ink upon the roller. When the transfer is successfully inked up, it is hung up to dry, and when dry is trimmed to size, placed in a damping book, and transferred to stone.
The exposed transfer, after wetting, and being placed upon the plate of glass, or zinc, may be developed in another way. First remove the superfluous water from the surface with a soft damp sponge, then rub it gently all over with a pad of cotton-wool dipped in a thin mixture of ink thinned with turpentine and well mixed with a palette knife (this ink should be a little thicker than ordinary copying ink); all the image must be covered with the ink. The turpentine is then allowed to evaporate, when by rolling with the glue roller from the body, the ink will clear away from the whites, leaving the lines sharp and distinct. Do not use too much pressure, else the ink may be removed from the lines, in which case cover the whole picture with a fresh coat of the thin ink, and again roll off. The subsequent operations are the same as for the other paper transfers.
The ink for this method is made by melting over a Bunsen burner, or paraffine stove,
| Chalk Printing Ink | 4 | ounces. |
| Beeswax | 1⁄2 | ounce. |
| Stearine | 1⁄2 | ounce. |
| Resin | 3⁄4 | ounce. |
When these are melted and well stirred together, set the mixture on fire and allow to burn for three minutes, then extinguish by putting the cover on the pot or pan, then pour it into a tin. When cold it is ready for use.
In handling the sensitized gelatine paper for transfers, every care must be exercised to keep the paper from being exposed to the action of light, before and after exposure in the printing frame, else there will be great difficulty in getting clean transfers.
CHAPTER IV. TOOVEY’S NEGATIVE TRANSFER PROCESS.
A good smooth paper is floated for five minutes upon finest picked
| Gum Arabic | 5 | ounces. |
| Water | 15 | ounces. |
| Bichromate of Potash | 1 | ounce. |
This is dried in the dark, then exposed to light in a printing frame under a direct negative. It is then laid, face down, upon a polished zinc or stone, if a line subject, or on a grained zinc or stone, if a half-tone subject; upon the back of the print several sheets of damp paper are laid, and then the whole is subjected to very heavy pressure in a hydraulic press, so that the water in the damp paper may be forced through the print and dissolve the gum in the unexposed parts of the sensitive gum coating (which is still soluble). The dissolved gum attaches itself to the stone, whilst the exposed parts being rendered insoluble by the action of light, the damp has no effect upon it, and the stone is protected in those parts.