A Manual Of Photography

CHAPTER VIII. the USE or ALBUMEN ON GLASS PLATES AND ON PAPER, &C. Section I.—Albumen on Glass. In the Technologist for 1848, M. Niepce de Saint Victor pub- lished his mode of applying albumen to glass plates. M. quart Everard followed ; and successively albumen, gelatine, serum collodion, and other substances, have been recommended for application on glass: but few of these substances have been found to answer so perfectly as albumen applied according to the directions of M. Le Gray. He recommends that the whites of fresh eggs equal to about five fluid ounces be mixed with not more than 100 grains of iodide of potassium, and about twenty grains of the bromide, and half that quantity of common salt.. He then directs you to beat this mixture in a large duh wit a wooden fork, until it forms a thick white froth ; to let it repose all ni-ht, and the next day to decant the viscous liquid which has deposited, and use it for the preparation of your g asses For this purpose take thin glass, or, what is much better, ground glass, on which the adherence is more perfect ; cut it the size of your camera frame, and grind the edges. The success of the proof is, in a great measure, due to the evenness of the coat of albumen. . „ To obtain this, place one of your glasses horizontally, the unpolished side above (if you use ground glass, which I think preferable), and then pour on it an abundant quantity of the albumen. ' Take a rule of glass, very straight upon the ends of which have been fastened two bands of stout paper steepedm white wax: hold this with the fingers in such a manner that they will overlap the sides of the glass plate about one-eighth of an inch. You then draw the rule over the glass with one sweep so as to take off the excess of albumen. The object of the slip of paper is to keep the glass rule from the 'àeeof the plate, and ensure a thin but even coating of the albuminous Thus, in making the paper band more or less thick, you >ary