COATING THE PAPER.
When filtered, the albumen should be poured into a flat dish a few inches larger each way than the paper to be treated, and levelled up by means of three wedges (see Fig. 256) so that an even layer of albumen is presented to the print. There should be a depth of at least 1 in. of solution over every part of the dish. This should be arranged upon a bench close to a fire, as the gloss of the paper depends upon the heat. The temperature should be about 90°. The higher the tem perature, the more brilliant will be the glaze, and consequently the more brilliant the print. If the temperature is allowed to fall much below 90°, the paper will have a dull appearance, and the image be somewhat sunken. This, however, is not a serious defect, as where brilliancy is desired other processes are available. It will be remembered that, in the " plain salted " process, the heavier the sizing the more brilliant the picture, owing to its being kept more on the surface of the paper. When the temperature is high, a heavier coating is obtained on the paper with a like result. Both single and double
albumenised paper are obtainable ; the latter having a heavier coating resulting insensitive spots on the paper. Floating for a longer time seems to have no in jurious effect, but if extreme brilliancy is desired the paper should not be left in the solution too long. In coating on a large scale, it is best to have two dishes of albu men, so that while one sheet is floating another may be laid down or taken off. The paper may also be drained and dried over wooden laths, as shown in Fig. 258 ; but this is not advised, as it is liable to cause unevenness. Manufacturers usually submit the paper when dry to heavy pres sure in a rolling press, to make the coating more even and to improve the gloss.
from two applications. The right side of the paper is then determined as explained OD D. 165. Moisten the back with a damp sponge lightly, and float it on the albu men, as described for sizing on p. 165.