American Hand Book of the Daguerreotype [15]
When perfectly dry, pulverize, and it is ready for use. With a little trouble you will obtain in this way a much better article than can generally be bought of dealers. For the last washing, alcohol, or a mixture of alcohol and water, is preferable."
Potassa Solution.--The use of a solution of potassa in the preparation of the plate was suggested in the early history of the Daguerreotype. It was thought to possess some peculiar property for improving the tone of the impression. It is used for moistening the rotten stone in polishing the plate, and may be prepared by putting about an ounce and a half of alcohol in a close bottle, and add half a stick of caustic potash. This will soon become of a deep red color. For use, fill your small bottle, having a quill in the cork, with alcohol, and add a few drops of the above, or enough to change it to a bright orange or saffron color.
A Substitute for the Hyposulphite Solution.--M. DAGUERRE recommends the use of a solution of salt water for removing the coating off the plate. I found this of some service at one time during my travels. My hyposulphite bottle got broke and its contents lost, so as only to leave enough for preparing gilding. I resorted to the use of salt solution, and found it to answer well. Make a saturated solution of salt in water. First wash the plate with clear water; then immerse it in the saline solution, when it should be agitated, and the coating will soon disappear. Another process with a salt solution of half the strength of the above is very interesting and effectual. The plate having been dipped into cold water, is placed in a solution of common salt, of moderate strength; it lies without being acted upon at all; but if it be now touched on one corner with a piece of zinc, which has been scraped bright, the yellow coat of iodine moves off like a wave and disappears. It is a very pretty process. The zinc and silver forming together a voltaic pair, with the salt water intervening, oxidation of the zinc takes place, and the silver surface commences to evolve hydrogen gas; while this is in a nascent condition it decomposes the film of iodide of silver, giving rise to the production of hydriodic acid, which is very soluble in water, and hence instantly removed.
This process, therefore, differs from that with hyposulphite. The latter acts by dissolving the iodide of silver, the former by decomposing it. It is necessary not to leave the zinc in contact too long, or it deposits stains, and in large plates the contact should be made at the four corners successively, to avoid this accident.
Gilding Solution.--To one pint of pure rain or distilled water add fifteen grains of pure chloride of gold, and to another pint add sixty grains of hyposulphite of soda. When dissolved, pour the gold solution into the hyposulphite by small quantities, shaking well after each addition. The soda solution must not be poured into the gold, as the gold would be immediately decomposed, and the solution turn black, and be unfit for use.
Some operators add muriate of potash and other substances, but these do not possess any advantage except in cases where it is necessary to bleach the solarized portions of the impression, and when such is the case, chloride of sodium (common salt) is probably as effective and is the most convenient. Add about a teaspoonful to two ounces of the gilding.
Solution, for Increasing the Brilliancy of the Daguerreotype.--This solution will have the effect to thoroughly cleanse the surface of the gilded plate and excite a powerful influence on the general character of the impression. To a solution of three ounces of water, in which is dissolved a quarter of an ounce of cyanide of potassium, add one teaspoonful of a solution containing six ounces of water and half an ounce of each pure carbonate of potash, alum, common salt, gallic acid, sulphate of copper, and purified borax. While the plate is wet, pour on a little, and heat it with a powerful blaze. The effect will be quickly produced, in from three to fifteen seconds. Rinse and dry,
Potassa Solution.--The use of a solution of potassa in the preparation of the plate was suggested in the early history of the Daguerreotype. It was thought to possess some peculiar property for improving the tone of the impression. It is used for moistening the rotten stone in polishing the plate, and may be prepared by putting about an ounce and a half of alcohol in a close bottle, and add half a stick of caustic potash. This will soon become of a deep red color. For use, fill your small bottle, having a quill in the cork, with alcohol, and add a few drops of the above, or enough to change it to a bright orange or saffron color.
A Substitute for the Hyposulphite Solution.--M. DAGUERRE recommends the use of a solution of salt water for removing the coating off the plate. I found this of some service at one time during my travels. My hyposulphite bottle got broke and its contents lost, so as only to leave enough for preparing gilding. I resorted to the use of salt solution, and found it to answer well. Make a saturated solution of salt in water. First wash the plate with clear water; then immerse it in the saline solution, when it should be agitated, and the coating will soon disappear. Another process with a salt solution of half the strength of the above is very interesting and effectual. The plate having been dipped into cold water, is placed in a solution of common salt, of moderate strength; it lies without being acted upon at all; but if it be now touched on one corner with a piece of zinc, which has been scraped bright, the yellow coat of iodine moves off like a wave and disappears. It is a very pretty process. The zinc and silver forming together a voltaic pair, with the salt water intervening, oxidation of the zinc takes place, and the silver surface commences to evolve hydrogen gas; while this is in a nascent condition it decomposes the film of iodide of silver, giving rise to the production of hydriodic acid, which is very soluble in water, and hence instantly removed.
This process, therefore, differs from that with hyposulphite. The latter acts by dissolving the iodide of silver, the former by decomposing it. It is necessary not to leave the zinc in contact too long, or it deposits stains, and in large plates the contact should be made at the four corners successively, to avoid this accident.
Gilding Solution.--To one pint of pure rain or distilled water add fifteen grains of pure chloride of gold, and to another pint add sixty grains of hyposulphite of soda. When dissolved, pour the gold solution into the hyposulphite by small quantities, shaking well after each addition. The soda solution must not be poured into the gold, as the gold would be immediately decomposed, and the solution turn black, and be unfit for use.
Some operators add muriate of potash and other substances, but these do not possess any advantage except in cases where it is necessary to bleach the solarized portions of the impression, and when such is the case, chloride of sodium (common salt) is probably as effective and is the most convenient. Add about a teaspoonful to two ounces of the gilding.
Solution, for Increasing the Brilliancy of the Daguerreotype.--This solution will have the effect to thoroughly cleanse the surface of the gilded plate and excite a powerful influence on the general character of the impression. To a solution of three ounces of water, in which is dissolved a quarter of an ounce of cyanide of potassium, add one teaspoonful of a solution containing six ounces of water and half an ounce of each pure carbonate of potash, alum, common salt, gallic acid, sulphate of copper, and purified borax. While the plate is wet, pour on a little, and heat it with a powerful blaze. The effect will be quickly produced, in from three to fifteen seconds. Rinse and dry,