A Manual Of Photography

232 PRACTICE OF PHOTOGRAPHY. plunged into it, one over the other, removing any air-bubbles which may form. Fifteen or twenty sheets being placed in the bath they are allowed to soak for half an hour, or an hour, ac- cording to the thickness of the paper. Turning over the whole mass, commence by removing the first sheet immersed, and hooking it up by one corner with a pin bent in the shape of the letter 8, fix it on a line to dry, and remove the drop from the lower angle by a little bundle of blotting-paper. M. Le Gray then remarks that French and English paper should never be mixed in the same bath, but prepared separately, as the “ English paper contains a free acid which immediately precipitates an iodide of starch in the French papers and gives to them a violet tint." The paper being dry is to be preserved for use in a port- folio ; even in this state it is not absolutely insensible. Third Process: To render the Waxed Paper Sensitive.— Make a solution of Distilled water ..................2325 grains. Crystallized nitrate of silver . . 77!“ and when this is dissolved add of Crystallized acetic acid . . . 186 grains. Papers prepared with this solution will keep well for a few days. M. Le Gray, however, recommends for bis waxed paper, and for portraits, that the quantity of nitrate of silver be increased to 155 grains: the paper must be used moist. The method of preparing these papers is to float upon an horizontal plate of glass either of the above solutions, and taking a piece of the iodized paper, to carefully place it upon the fluid, taking great care that no air-bubbles interpose. The paper must remain a short time in contact with this sensitive fluid until chemical combination is effected. Four or five minutes are required for some papers, and eight or ten seconds are sufficient for other kinds. When a violet tint appears tins should be removed. For those papers which it is desirable to keep for some time, as during a journey, it is recommended that into one vessel of porcelain you put about five or six millilitres of the strong aceto-nitrate above described, and into another some distilled water : you plunge completely both sides of the waxed and iodized paper in the first fluid, and allow it to remain about four or five minutes ; withdraw it, and plunge it immediately into the bath of distilled water, in which let it soak for not less than four minutes. When these papers are carefully dried they may be preserved for some time for use, and by lessening the dose of nitrate of silver this period may be considerably prolonged. It