A Manual Of Photography

216 PRACTICE OF PHOTOGRAPHY. In another bottle dissolve 75 grains of nitrate of silver in a wine-glass or two of water ; when well dissolved, you add to it a saturated solution of chloride of sodium, until the white precipitate ceases to fall; allow it to repose a short time, and then decant the clear liquor, and gather the precipitate of chloride of silver, which you dissolve in the other hottie of hypo- sulphite of soda ; by means of this solution you obtain directly black tints upon the picture. The older the hyposulphite of soda is, the better; when it gets thick, you must add a fresh solution of hyposulphite alone, without the cliloride of silver, the old containing an excess, which it has taken from the proofs already immersed in it. You must not filter it to take away the deposit, but only let it repose in a large bottle, and decant the clear liquid for use, leaving the sediment to be redissolved by fresh solution. '“By leaving the proofs a longer or shorter period in the bath, you can obtain al1 the tints from the red to the black, and clear yellow ; with a little practice, you will be sure to get the tint vou desire. You must not leave a proof less than an hour in the bath for it to be sufficiently fixed, and it can remain three or four days to obtain the sepia and yellow. By heating the hyposulphite of soda I accelerate the operation ; but we must not then leave the proof for an instant to itself, as the rapidity of action is so great, that the picture might be com- pletely effaced. “ By adding to the preceding solution about one fluid ounce of liquid ammonia, I obtain pretty bister tints, and very pure whites. The English paper is exceedingly good for these tints. “ I obtain also fine velvet-like tints by putting the photograph (when taken out of the hyposulphite of soda) upon a bath of a salt of gold, using 15 grains of the chlorine of gold to one pint and a half of distilled water. “Fine yellow tints are obtained by placing the proof (if too vigorous) first in a bath of hyposulphite, and then in a bath composed of one pint and a half of water, and one fluidounce and a half of hydrochloric acid; washing it perfectly in water. Liquid ammonia, employed in the same quantity as last men- tioned, gives remarkably fine tints. 6- When the proof is the colour you desire, wash it in several waters, and leave it two or three hours in a basin of water, until, touching it with the tongue, you perceive no sweet taste which indicates the presence of hyposulphite of silver ; then dry it by hanging it up, and it is finished. The batli may contain as many proofs as can be conveniently placed in it.” The following fixing processes are rather more curious than