In order to obtain fully and completely the character and correct reproduction of the drawing, without special expense of artistic help, it is advisable to use a photographic print as proof. It should be noted that for pen drawing on smooth paper with greasy tusch or ink, for chalk drawings on a prepared grained paper done as previously mentioned, with greasy lithographic chalk, the drawing should be transferred direct to zinc or stone in order to save having to make subsequently a photographic print.
If a pencil, red crayon, or other proof is used for an autographic drawing on paper with the idea of transferring it direct to stone or zinc, a suitable photographic print may also be used on suitable paper without any disadvantages.
For the prints all photographic papers without glaze, such as ordinary plain salted paper, Eastman’s positive bromide paper, and others, may generally be used. Glossy or albumenized papers are not suitable for this, as the ink runs, and does not form solid clean lines. {85}
The best of all, however, is cyanotype paper, as even with very deep printing it keeps the details in the shadows open, and on account of its blue tones is more suitable for the subsequent drawing with black tusch. When, however, prussiate paper is not handy, and subjects with fewer shadows and less details are to be treated, any of the other papers above-mentioned may be used.
If ferro-prussiate paper is to be used, the same may be prepared as recommended on p. [23.]
The so-called salted or plain paper is prepared as follows:—A sheet of well-sized post paper is first bathed in a solution of—
| Ordinary salt | 1 | part |
| Water | 25 | parts |
and then sensitized in a solution of silver nitrate 1 : 12. It is printed till the print has assumed a fairly full brown tone, and all the details in the shadows are well printed out. It should then be toned in the following toning bath:—
| Distilled water | 1000 | g. |
| Sodium acetate (twice fused) | 15 | g. |
| Solution of gold chloride (1 : 100) | 25 | g. |
till the print has assumed a deep dark brown tone. It should then be fixed in a solution of sodium hyposulphite, 1 : 15. It should be printed rather deep, as in toning and fixing the image loses in depth. It is moreover unnecessary in this case to make a beautiful print; the chief thing is only that all details of the image should be clearly seen. The print is then well washed in frequent changes of water and then dried.