When transferred, the image is treated in exactly the same manner as an ordinary transfer on stone or zinc.
The enamelled double transfer paper sold for double transfer carbon work may be used for photo-litho. transfers by floating it upon
| Albumen | 5 | ounces. |
| Water | 20 | ounces. |
| Saturated Solution of Bichromate of Potash | 3 | ounces. |
| Liquor Ammonia | 10 | drops. |
and then dried.
Paper thus prepared must be kept in a dry air-tight case, and just before using is laid face down upon a smooth litho. stone, and pulled through the litho. press. After this, it is placed in contact with the negative in the printing frame, and exposed to light until the details are visible. Although the progress of the action of light can be seen, the frame must not be opened too often, or the paper is apt to expand and blur the image. After exposure the print is inked up, developed, and treated exactly as explained above.
The ink suitable for inking up the stone, previous to laying upon it the exposed print, is composed of
| Best Chalk Litho. Printing Ink | 3 | parts. |
| Mutton Fat | 1 | part. |
Put the ink and fat into a small iron or earthenware pot, and place it over a Bunsen burner, or a paraffine stove, or on the hot plate of a kitchen stove (but not over an open fire); allow the heat to melt the two ingredients, stir so as to incorporate them thoroughly; take great care not to allow it to catch fire; if it does, at once extinguish the flame, as the firing would be apt to spoil the ink. When thoroughly melted and incorporated, pour into a tin, or pot, for use when cool; the time occupied in making this ink will not exceed twenty minutes. The mutton fat is obtained by dropping solid kidney suet (shredded) into a pan of clean boiling water, then allowing to cool, when the fat is taken off the surface of the water, freed from damp and stored for use.
Another formula for the preparation of paper, to be inked up, after printing in the same manner as the above transfers, is to coat paper twice with the following preparation, drying between each coat: arrowroot, 1 ounce; wet this thoroughly with 5 ounces of cold water, stirring well with a spatula, adding more cold water, if necessary, to moisten the lot; then pour over it 20 ounces of boiling water, stirring all the time; if, when the 20 ounces are added, {135} the arrowroot has not thickened, add more boiling water until it does do so; now add 1⁄2 an ounce of powdered bichromate of potash and stir until dissolved; then strain through muslin into a warm dish and float the paper upon it whilst hot, and dry at a temperature of 70° F.
If the bichromate of potash be omitted, the paper may be prepared in quantity and stored away for future use, being made sensitive by floating for five minutes upon