With plates of large size the solution may be poured over the plate, and it may be necessary to repeat this operation several times to ensure an even and sufficient coating. Immediately previous to the application of the chromated layer the negative should be rapidly washed over with warm water. A sufficient quantity of the chromated solution must be allowed to remain upon the plate, and the latter warmed in a horizontal position over a spirit lamp. When steam arises the plate has to be held in a perpendicular position for a minute, restored to its horizontal state, and again warmed until the coating of the plate is quite dry, care being taken that at no time the plate is so heated that it becomes unpleasant when placed upon the hand. Place the plate face downwards upon a black support, print until the fine lines are plainly visible, when the plate may be washed and further treated as in Collotype.” CHAPTER XVI. ALLGEYER’S COLLOTYPE PROCESS. =Half-tone Negatives= must be softer, and possess more half-tone than requisite for silver printing. When examined by transmitted light, they should appear clear in the shadows, and not too dense in the half-tones. =Line Negatives.=—Negatives for the reproduction of line subjects need not possess the absolute opacity requisite for silver printing, but the lines should be clear glass, entirely free from fog or deposit. =Stripping the Negative.=—The fixed and washed negative is flooded over with a solution of gum arabic in water (1 to 20), to which has been added a few drops of a solution of chrome alum (1 to 60). Allow to dry, retouch with lead pencil, and edge with tallow to prevent overflow, place upon a levelling stand, warm moderately, and coat with a solution of gelatine 100 parts, glycerine 15 parts, alcohol 100 parts, water 400 parts, allow to set, and place against a wall to dry, the coated side outwards, the plate standing upon clean blotting paper. The operation of drying will probably take a day or two, and when quite complete, it is again coated with collodion, and again dried. After allowing to remain in a damp place for two or three hours, cut around the edges with a knife, and strip off the film, which may then be printed from either side, and after use may be stored in a book, the leaves of which consist of smooth paper. =Reproduced Negatives.=—Coat a plate with a solution of gum arabic 50 parts, dextrine 50 parts, honey 10 parts, sugar 25 parts, glycerine 5 parts, bichromate of ammonium 15 parts, ammonia 50 parts, water 1,000 parts. After drying, expose under a negative, dust over with graphite, coat with plain collodion, and wash in clean water until all yellowness disappears.