268. To silver paper that will keep, make a solution of nitrate of silver, thirty to forty grains strong; add to this two grains of citric acid to each ounce. After the citric acid is men surface of the paper is now laid upon the film, the shutter made fast by the springs, so as to bring paper and negative in close contact uniformly all over, and the exposure made to the light, so as to allow the rays to fall horizontally upon it.
254. The exposure of the paper to the light is governed by the various conditions of the light, the temperature, the nature of the negative, and by the paper used. To secure a good print, the paper should be floated long enough to produce a clear and even picture, without any mottled appearance in the background; it should also be a little bronzed in the deep shadows, and it should be fumed long enough, that, when printed, it will assume a rich purple tone. In many cases, half a minute will be found sufficient to float the paper upon the silver, and in some cases, where the negative is very dense, the print will be improved by omitting the fuming altogether. The exposure ended, the prints must now be gathered together for the after manipulations.
dissolved, add ammonia as long as a precipitate of citrate of silver is formed; then redissolve the precipitate by the addition of nitric acid. Care must he taken in adding the nitric acid to add just enough to quite redissolve the precipitate, leaving a very slight excess of nitric acid. Float the paper in the usual manner; and, after drying, store away hetween sheets of blotting-paper. - H. T. Anthony.
To preserve sensitized paper, dip sheets of blotting-paper in a saturated solution of bicarbonate of soda; hang up and dry. When your day's work of printing is over, lay your surplus sensitized paper between these sheets, in a large book; the paper will keep as pure in color as when first silvered, and will not turn if left so for a week. This simple method may prove a great economizer, especially when after silvering a good lot of paper the day suddenly grows dark, and the light slow and almost devoid of printing power. - J. L. Gihon.
"We silver and fume our paper the night before it is to be used, and for several reasons; in warm weather the evening air is cooler and favors the keeping of the paper, and I find it much more comfortable working with plenty of fresh air than being boxed up with a gas or kerosene light. Then, again, you are very certain no white light reaches the paper until it comes through the negative, and I am fully convinced that daylight, small it may be In quantity, is one great cause of yellow paper; and I, too, find that paper prints much nicer several hours after fuming than just after. Second, instead of putting prints into acid water direct, put them into a bath of plain water first. They will redden much more evenly and are easier to handle. - Julius Hall.
In a few words, let me recall some of the points to be remembered in order to obtain success in printing. Keep the paper damp before silvering, so that it may take the silver uniformly and quickly, and also as a guard against one source of blisters. Always keep a sufficient quantity of solution, and never think of starting to silver without being certain of the condition of your bath both as to strength and alkalinity. If you would have your paper print rich, do not allow it to become too dry before printing. If you would have your prints resist the atmospheric influences as much as possible, do not be afraid to tone them well. If these requirements are carefully attended to, success will follow. - H. A. Webb..
255. A bath of tepid vater is prepared in a dish or tank, into which the sprints are quickly or entirely immersed, one after the other, and lowed to remain from three to five minutes,at the end of which the water is changed, and the oparation repeated. The first two water removes considerable free nitrate of silver, and should be saved in a cask, the silver precipitated by means of salt. Two or three more changes of water are now necessary before the prints are ready for the following treatment in several changes of water, until the odor of the acid is entirely removed, when they are ready for toning.
256. Another bath of tepid water is now provided, to each gallon of which about one ounce of acetic acid has been added, stirring thoroughly so as to secure the complete acidifying of the water throughout the vessel. Now completely immerse the prints one by one, and allow them to remain, say, ten minutes, keeping them continually in motion. The ob-je»t of this operation is to render the next one - toning - easier by changing the color of the prints, so the effect of the toning an be more readily observed and the toning itself is thus accelerated to a considerable degree. The acid - water being next poured off, the prints are again washed
255. When the print comes from the printing-frame, it contains several substances which must be removed. There are the violet subchloride, Ag,Cl, the red or yellowish-red suboxide, Ag2,02, and the free nitrate, AgNo3,. The free nitrate being soluble, is removed by washing; after which the subchloride and unreduced chloride must bo removed from the print, as they are capable of further reduction by the light. Who has not wished that the print might be taken from the frame just at the right moment, and so preserved? But that which constitutes its beauty of color at that point is the violet subchloride on a substratum of the red suboxide. If it is now placed in the fixing - bath, the subchloride is dissolved, and the suboxide left. But the color in this condition is not satisfactory. So a substance was sought for to supplement this suboxide, and compensate for the loss of the subchloride. The search was suc-cessful and the result admirable. - W. H.Sherman.