The plate being dry it is exposed under a good ordinary (reversed) negative until the whole of the details are well out. Time the exposure by means of an actinometer.
After exposure under the negative, remove the plate from the printing frame and in the dark room cover it with litho. transfer ink by means of a leather roller, taking care that the whole of the surface is well coated with the ink. Now place it in clean cold water for three or four hours, then with a soft {146} sponge remove as much of the ink as will come away. This operation will take time, as every care must be had not to scratch the film.
Now rinse the plate under the tap and allow it to dry.
When dry soak it in cold water for half an hour, then place it on the press (an ordinary letter press), and with a sponge and soft cloth remove the superfluous water from the film; then roll up with a leather roller charged with litho. transfer ink as thick as can be worked. When the image is properly inked up pull a transfer upon good Scotch transfer paper.
Perhaps the first two or three pulls will not be satisfactory; therefore, it will be best to pull a few before using the transfer paper, damping and wiping between each pull just in the same way that is done in printing from a lithographic stone.
A good transfer being obtained, it should be given to a lithographer to put it down upon a grained stone, an operation which requires great skill and experience. The student’s interest will be best consulted by not attempting to give a description of how to transfer to a grained stone.
Another formula for a sensitive coating for the copper plate is
| Gelatine | 1 | ounce. |
| Water | 6 | ounces. |
Soak the gelatine till soft; then melt, and add one drachm of bichromate of potash in powder; stir until dissolved; add twenty grains of good fresh dextrine and let the mixture cool to about 120° F.; then add one drachm of liquor ammonia and six ounces of alcohol. The subsequent operation of coating, etc., is the same as above.