DEVELOPMENT OF THE PRINT.
If convenient it would be an advantage to have the above-mentioned apparatus set up close to the window or other situation where the printing is actually carried on in order that each print may be developed and finished off forthwith,; the reason for this will, I think, appear as we proceed.
Development—that is, the changing of the print from the partially visible condition to its full degree of intensity—is practically instantaneous. The image does not gradually attain its maximum strength as in a negative or bromide print, but does so within a few seconds of its coming into contact with the oxalate of potash solution.
Fig. 1.
Having put into the dish on the tripod stand sufficient of the saturated solution of oxalate of potash to cover the bottom of the dish to the depth of half an inch or an inch, we light the lamp or stove and bring the solution up to a temperature of about 70° Fahrenheit. This may be tested with a thermometer or may very well be guessed by touch; we merely require the solution quite warm, but not so hot as to cause the slightest inconvenience if the fingers are placed therein. This will be a sufficiently accurate guide as to temperature.
In case any dust or scum should have accumulated on the surface of the bath, wipe the surface of the solution with a piece of clean paper, and now take the first print to be developed in both hands, giving it a decided curl, or roll it round into a cylinder sensitive side out, so that it naturally takes a curled-up form (Fig. 1). We now take the print to the dish containing the oxalate solution without previous washing and without exposing the paper to the influence of light or moisture, and lowering the edge of the paper held in the left hand, sensitive side downwards, until it touches the fluid quickly and smoothly bring the rest of the print down until the right-hand end finally reaches the solution, then give it a sliding sort of shake in order to set free any bubbles of air which may be imprisoned under the paper, and then on raising the paper again after five to ten seconds, the image will be found to have come out to the full degree of visibility, which the amount of exposure had paved the way for.
The paper may be returned to the oxalate bath for a minute or two longer if it be thought desirable, though only in the case of a very cold bath is any effect produced on the print by the oxalate after the first few seconds. The print is then passed direct to the hydrochloric acid bath, which should be ready in a dish close at hand, and the print is now practically finished.
Before placing the print in the acid bath it may be noticed that the portions of the print not affected by light still remain yellow, and this yellowness the acid bath removes almost at once.