The Invention of Lithography

by Alois Senefelder

(2) The method given is the best; but if the warming of the stone is difficult, there is a method applicable to cold stones. The etching-ground is dissolved in oil of turpentine and laid on the stone with a clean ball. A stone so treated must be put away for at least a day in a place safe from dust that the oil of turpentine may evaporate.

To tint this etching-ground, it may be blackened by smoking with a candle, as in the first case; or color, such as lampblack or vermilion, may be mixed-in before it is applied. If one wishes to be very certain that the stone will bear the etching well, it may be coated, very thinly indeed, with a solution of very firm chemical ink after applying the etching-ground.

The design is traced through this coating to the stone. It may be transferred, also, but in that case, as soon as the transfer is on the stone, it must be coated thinly once more with a solution of chemical ink that does not, however, contain any lampblack or other coloring-matter, but is transparent. This is necessary to fill out any little holes and other injuries that may have been caused by the pressure during transfer or by the inequalities in the transfer paper.

The designing with the needle is done as in the engraved manner, except that the design is merely cut into the coating.

When the design is complete, the stone is laid into the etching-trough and diluted aquafortis, muriatic acid, or strong wine vinegar is poured over it repeatedly, according to the depth that the lines are to have.

If it is desired to etch so as to produce various tones,—some strong and some delicate,—after the manner of the copper-plate etchers, the pouring of acid should cease as soon as the very finest lines of the design have been etched sufficiently. Wash away every bit of acid with clean water and let it dry. Then, with a small brush and chemical ink, coat all parts that are not to be etched further. It is well if the chemical ink used for this purpose contains a little more soap than usual, so that it can penetrate well into all the depressions and leave no little holes. The coating must be done very cautiously, and it is better to paint on too much ink rather than too little, as the design will appear very dirty if etching fluid should penetrate here or there through the coated portions.

When the ink is dry, etching is resumed till the second tones have been etched as far as desired. Then the procedure is repeated, these second tones being coated. Thus one continues till all gradations of shading have been reached.

When the stone is fully etched, clean water is poured over it, and then all the parts that have not been coated with chemical ink are treated to a covering. The object of the previous coatings was to prevent access of acid to the parts; but at the same time the ink prepared the parts. Therefore the remaining portions of the design also must be sated with ink before the stone is inked-in for printing.

Let the stone dry and then pour on it as much oil of turpentine as may be necessary to dissolve this whole ground coating, which then is wiped off with a woolen rag wet with gum solution. Then the stone maybe inked-in and printed.

If an error is observed before etching begins, the first question is if the defect is deeply engraved in the stone or if it has been drawn merely through the ground coating without affecting the stone itself materially. In the latter case it is necessary merely to cover the defective place with chemical ink and draw into it the correction. If the error has been graved deeply into the stone, it must be covered for the time being, but nothing new can be drawn there. To do this, one must wait till the plate has been etched and rubbed-in with color. Then the incorrect part is scraped or ground off as evenly as possible, the place prepared anew with aquafortis and gum, and the correction made with the steel needle.