260. I take two drachms of nitric acid and three drachms of hydrochloric acid; in that I can dissolve a five - dollar gold piece. That is pure enough; the copper is an advantage rather than a detriment. In this way you have one hundred and thirty-five grains of gold. Reduce that so as to have eight grains of gold to the ounce, or one grain to each drachm, and you will always know when you pour it out how much you have. That will give you about sixteen or seventeen fluid ounces to a five - dollar gold piece. That will keep. You may put in salt if you choose; I sometimes do that. This solution will go farther than any you buy. A few hours before you use it, neutralize it with bicarbonate of soda, borax, or any of the alkalies you have a fancy for, or according to the tone you desire. Bicarbonate of soda will give you a brown tone, and borax a black. Make it up a few hours before you want to use it, so that it will turn litmus - pa|per blue, and I do not believe you can prepare gold to make better tones. when you make this solution it i< acid, but you can neutralize it with bicarbonate of soda down to the point where a drop of it will turn green, or you can make it perfectly neutral, and add a little aqua regia. - H.J.Newton.
be applied, and the resulting mass well washed and dried, twice. To every grain of gold used, add one drachm of water.
261. From the toning solution the prints are now removed to the fix-ing-bath.
Hyposulphite of Soda,.......................
Carbonate of Ammonia,.......................
The prints should remain in the above solution for fifteen or twenty minutes, according to temperature, and constantly turned over singly to insure thorough fixing, after which they should be well washed, until every trace of hypo is removed.
261. On removing the prints from the toning - bath, wash them several times in pure water, then place them one by one, if possible, in a bath containing three or five grammes of pure muriatic acid to a litre of water: here let them float, moving them about for a few minutes, then wash them further for two or three minutes in pure water to remove the acid. On warm days the operation should last longer than on cold. The prints are then placed in the fixing - bath, and in those rare cases when the finished prints have a slightly yellowish tone after the removal of the acid, should be first put for a couple of seconds into a solution of five grammes of ammonia to a litre of water; then washed once, and placed in a hyposulphite of soda bath. In this way any alteration of tone is rendered impossible. - J. L. Gihon.
See that the hypo is not acid. It should be neutral, or even slightly alkaline. The hypo should be made up fresh every day, especially during summer. Drain the prints well from the hypo, and place in strong solution of salt for five minutes, moving them about all the time, and then put them in running water for three hours. It is better to make the hypo arid salt solution two or three hours before using it, as both hypo and salt make the water several degrees colder. The neglect of this is one common cause of blisters. - H. C. Bridle.
There is a diversity of opinion among photographers about the strength of the fixing-bath, some using it much stronger than others do. I am inclined towards having a weak bath, and fixing a longer time than I would with a strong bath, as the action will be more gentle, and on the whole better results are obtained by so doing, and blistering and bleaching are, in a great measure, cured. It is very important that the hypo bath should be made up every time you require its use, as old hypo-baths are very injurious to the prints. Take a two-gallon bottle, and place in it about ten pounds of hypo crystals, fill up with water, shake well, and label this bottle, "Sat. Sol. Hyposulphite of Soda." It is now ready to use in making the bath as per formula given below. To make sure of this hypo solution becoming saturated, prepare it at least two days before you wish to use it. Just before using, shake the contents in the bottle for about two minutes. When you wish to make the bath, take of
Sat. Sol. Hyposulphite of Soda, ...............
Sat.Sol. Bicarbonate of Soda,.......................
Larger quantities in same proportion. Make this bath in a dish which is kept expressly for this purpose, and this alone. - C. W. Hearn, in the Practical Printer.
262.One of the chief evils of the printer's life is the phenomenon known as " blistering" of the prints. Much speculations has ensured as to its cause and it is generally conceded to be governed largely by the temperature of the solution and wash- waters used. If there are uniform in temperature, "blister" are not apt to occur. Another method of preventing them to remove the prints from the fixing - bath to salt solution.
Allow them to soak in this for say ten minutes previous to the final washing.
263. The great blemish upon the character of photographic prints is that they oftentimes "do all fide as a leaf" All sorts of efforts are made to prevent this, hut the most effectual is that of carefullv washing them in several changes "of water. Where it can be had, running water is the best, for it is self - changing; but the same and is accomplished by changing the prints with the hands from one water to another, using a clothes-
262. To avoid blisters, have all your washings and solutions the same temperature as near as possible; remember, your solutions act more perfectly and energetically if warm; about ninety degrees is the best for the above use. I can make blisters all the time by changing the temperature of solutions, that is, from warm to cold, or cold to hot. If all your washings and solutions are of one temperature, you will never be troubled with blisters. - A.
Hesler. As an absolutely reliable remedy against the formation of blisters on albumen paper, lay the paper, with the prepared side, on a sheet of blotting-paper, and then wash the back of it with a very damp sponge. The sheet thus handled must dry in the air, as drying with heat will cause red spots, especially when pink paper is used. - Dr. J. Schnaus.