United States or Somalia ? Vote for the TOP Country of the Week !
"In using solutions of cyanide of potassium, the workman should not immerse his arms into them, otherwise it occasionally happens that the solution produces very troublesome eruptions over the skin." Hyposulphite of Soda. This salt forms one of the important chemicals for the Daguerreotype operator. Its application to this art is of an interesting nature.
The cork which serves to adapt the bent tube to the bottle A is now just removed for an instant, the other end remaining in the water in bottle B, and about two or three ounces of the dilute acid are poured in upon the hyposulphite, after which the cork is immediately replaced.
In addition to developers we must have what is called the "hypo" fixing bath. This is a solution of hyposulphite of soda, a chemical which is used in development and which renders the plate no longer sensitive to light, but dissolves that part which has not been acted upon by the developer.
Another and less dangerous source of these specks is organic matter contained in the solution employed in dissolving the chemicals, or the water in washing. Much of the hyposulphite of soda in market contains a sulphuret, which, coming in contact with the silver surface, immediately causes oxidation.
The zinc may be supposed to remove oxygen from the acid sulphite, NaHSO , giving hyposulphite, NaHS0 . The reduction of the acid sulphite is best performed in a cask, which can be closed at the top, so as to avoid entrance of air. The liquid is then mixed with milk of lime, and after again thoroughly stirring, the liquid is allowed to settle, and the clear is decanted into the dyeing-copper.
On mixing the following solutions, sulphur separates, and the brass becomes covered with iridescent crystallizations: cream of tartar, 75 grains; sulphate of copper, 75 grains; and water, 10 oz. Hyposulphite of soda, 225 grains; and water, 5 oz.
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.
With the following solution, all the shades of brown, from orange-brown to cinnamon, are obtained: chlorate of potash, 150 grains; sulphate of copper, 150 grains; and water, 1 quart. The following solution gives the brass first a rosy tint, and then colours it violet and blue: sulphate of copper, 435 grains; hyposulphite of soda, 300 grains; cream of tartar, 150 grains; and water, 1 pint.
The filtered concentrated saline liquid will afford, on cooling, a large quantity of pure and beautiful crystals of hyposulphite of soda." Hyposulphite of Gold. This compound salt is by a few considered preferable to the chloride of gold, but our experience has induced us to use the latter, believing we are enabled to produce a more brilliant and warm-toned impression with it.
Vast quantities of the hyposulphite of soda, which, we shall see, plays an important part in the process of preparing the negative plate and finishing the positive print, are also demanded.
Word Of The Day