(1) An inconvenience which has caused no little trouble to workers with gelatine plates is the length of time they take to dry. A collodion plate can be held to the fire and dried in a very short time; but a gelatine plate under the same conditions would melt and run. Now, a gelatine plate may, under different conditions, be dried quite as rapidly as a collodion plate; it is possible to take a negative, dry it, and print a proof in considerably less than 1/2 hour.
The principle is simply to remove the superfluous moisture before holding the negative to the fire, and this can be done by applying a piece of perfectly clean blotting-paper to the surface of the gelatine, using at first a moderate pressure, and increasing this pressure to any degree required. The blotting-paper will in no way injure the negative, and any stray pieces of fluff will dust off when the plate is dry. Still, it is better to carefully dust the blotting-paper, and to remove any stray pieces of material before it is applied. It will now be found that the negative can be dried at any degree of heat in the space of £-2 minutes. This fact led to the following: -
If a gelatine negative be dried as above, at only a moderate heat, it will not perceptibly differ from a negative which has been allowed to dry spontaneously; but if a negative from which the superfluous moisture has been extracted by blotting-paper be exposed to a greater heat, the whole complexion of the negative is altered. Not only does the film become horny and tough, but the picture on it appear! in relief - so much so that it seems quite possible to produce a cast from the negative capable of being printed from in an ordinary press. This is an extension of the principle in which hot water is used as a developer; but this lattor does not seem either as simple or efficacious as the method suggested. (J. J. S. Bird.)
(2) After well washing, place the plate in a bath of methylated spirit for 2-3 minutes; afterwards flow 2 or 3 times with common methylated sulphuric ether. The negative will dry in a current of air in 2-3 minutes.