Photo-engraving, Photo-etching and Photo-lithography in Line and Half-tone / Also Collotype and Heliotype

by W. T. Wilkinson

Fig. 8.

Fig. 6 shows a print of the little picture given during the process of middle and deep etching, and admits of an instructive comparison during the progress of the work. {92}

Proofs are made from the cleaned plate (the back of which has been scratched clean) in the following manner: Upon a good lithographic roller place a quantity of the best ink and coat the etching uniformly. Help the shadows along by dabbing on some ink with a leather pad. When this is done, carefully rub off the excess in the lightest spots, and fix the plate in the rolling-press; place on it a sheet of well-calendered tissue paper, next a sheet of writing paper, a sheet of Bristol paper, and a cardboard. With very little pressure (the thickness of one cardboard less than in the transfer) draw it through. If the print is too weak, place paper below, sheet by sheet. The stronger spots may be blackened separately.

FINISHING AND MOUNTING THE PLATE.

The first thing to be done is the removal of the black edge left by etching and the sawing out of such spots in the drawing as were spared for this from the beginning. The waste may be removed by means of a circular saw or a fine-toothed carpenter’s saw. Do not, however, forget to leave behind a margin of about three millimetres for the purpose of nailing the plate to the wood. The edges must be smoothed with a graver, filed and chipped off to a suitable plane, since sawing produces a sharp edge.

To remove the spots spared in the drawing, bore a hole through the metal at that spot with an American gimlet, introduce a scroll saw, and thus cut out the metal. The edge should be worked over with a dog-leg chisel.

By aid of the borer we also make the conical holes in the edge, through which the nails are to be hammered. Elevations caused on the back of the plate by boring should be removed by filing.

The block of wood which is to raise the height of the plate to that of type should be cut from perfectly dry maple, oak, or mahogany wood. With the plate it must just reach to the top of the type; the sides must be parallel, and all should be perfectly smooth.

Cutting at right angles can be done with a circular saw or with the aid of a mitre saw used by printers for such work. For exact examination of height, {93} pass the block and zinc through the caliber-bridge (Fig. 9). Roughen the base and top surface of the block with a toothing-plane. When convinced that the block fits perfectly, nail the etching upon it, taking care to drive the heads of the nails well into the holes provided for them, otherwise they will show in the print. If other small details are noticed, they may be removed with a dog-leg chisel.