Development and Developers
developed with a developer other than pyro, the clearing bath is not necessary, and the negatives may be removed direct from the hypo to the washing tank.
Washing. After treating with the clearing solution, the negatives should be again well rinsed, and placed in a grooved washing tank, in which they are to be washed for not less than 2 hours, the water running continuously through the tank or being frequently changed. In placing film negatives in the grooves it is best to put two films back to back in one groove, as they stand up better in this way. When finished washing, hang the film negatives up to dry ; spring clips are most convenient for this purpose, the films being suspended by one corner.
The negatives may be printed from as soon as perfectly dry, but if this be done without previously protecting them with a coat of varnish, there is always a danger of the silver from the sensitised paper staining the negatives.
Special Transparency Plates for Lantern Slides. - Instructions for Use. They are equally suitable for contact printing or reductions in the camera. For contact printing by gas-light, using the light of a good fish-tail burner at a distance of 12 inches from the flame, any time from 10 to 60 seconds' exposure may be required, according to the density of the negative, more exposure being necessary when it is intended to develop with pyro for brown tones, than for black tones with hydrokinone or amidol. Very thin negatives should be exposed at a greater distance from the light and very dense ones nearer to it. Exposure may also be made by diffused daylight in the dull light of an ordinary room ; it is, however, far more difficult to judge the correct time of exposure, therefore it is preferable to use artificial light. It is important that as