The Art and Practice of Silver Printing

give a detailed account of each. In case the reader may desire to

sufficient quantity for the purpose in hand. Suppose we are going to make up 20 ounces of solution, then about 18 ounces of white of egg must be found in the jar. One point to settle is the amount of salt to be used to each ounce of albumen. It must be recollected that a medium quantity is the best for medium negatives; anything between 20 and 40 grains per ounce may be used. We prefer ourselves about 25. Supposing this quantity to be used, we proceed to dissolve 500 grains of chloride of ammonium in 2 ounces of water, and add it to the albumen. It has been proved that as regards colour of the picture, it does not matter what chloride is used. To prevent crystallization, it is better to use ammonium, which contains a greater amount of chlorine than do sodium or potassium chlorides. It must now be beaten up till it is in a froth. This breaks up the fibrous matter, and on subsidence the liquid will be found to be limpid. The most convenient implement with which to beat up the albumen is the American egg-beater. Three or four minutes' work is quite sufficient to make the whole into a froth. An ordinary culinary whisk, such as is used in the kitchen, may also be put into requisition, or, in default of that, a bundle of quill pens. A lesson in producing a froth can be learnt from the c

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e evident that there is considerable economy in taking the whites wholesale. As a rule, about three gallons of albumen will coat two reams of albumenized paper. Mr. England (to whom we are indebted for so many of our remarks on albumenizing paper) procures ab

own firmly the paper it is proposed to employ over this. If the black ink marks are indistinguishable, the paper will do as regards this quality, as the light reflected from the surface which gives the impression of whiteness to the eye is much stronger than the light which penetrates through it, and is absorbed by the black lines. As to qual

from bubbles, is poured in, and should be of a depth of at least 1/2 an inch. Suppose the smaller size to be coated, before commencing, the paper is taken by the two opposite corners, the hands brought together, and the convex side brought on to the surface of the fluid; the hands are then separated, and the paper will gradually float on the surface. One corner should be gradually raised to see that all air-bubbles are absent. If there be any, they should be broken with the point of a glass rod, and the paper again lowered. Bubbles can usually

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s of one end, one in each hand, and to lower the surface near the end of the dish, and gradually draw the

The sheets, when slowly removed from the bath, are allowed to drain a few seconds, and then thrown over wooden rods of some two inches in diameter, which are removed to

o the line; but this is a mistake, as it will nearly always be found, on sensitising the paper and exposing it,

lly it is due to imperfect beating up of the solution. Some papers are not readily coated with albumen, in which case the remedy given above may prove effectual; or a little solution of oxgall may be equally well applied. A want of gloss in the dried albumen may be due to too long a floating on the fluid, or to floating and drying the paper in too low a temperature

application of blue litmus paper to it; the blue colour disappears and is replaced by a red tint. When in the alk

found to answer admirably, placing the albumenized side next the bed. This rolling should not be necessary if attention be pai