The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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Silver Oxide                                          Sizes, Photographic
Silver Oxide (Ger., Silberoxyd; Fr., Oxyde d'argent; ItaL, ossido d'argent). Ag.,0 = 232. May be obtained by adding pure solution of any caustic alkali, except ammonia, to a solution of nitrate of silver, when the oxide is precipitated as a brownish black precipitate. It is but little used now, except to purify silver solutions from copper, but was used in the old wet-plate process to purify the silver bath. It cannot be made by heating silver in a current of oxygen or air, because, although union takes place, the whole of the oxygen is given up on cooling.
Silvering Glass. See Mirror.
Silver Sulphide (Ger., Schwefelsilber; Fr., Sulfure darge?it; Ital., Solfuro dargento). AgaS = 242. This salt is met with in residue recovery, and is the resultant salt of the decomposition of hyposulphite of silver in prints. It is insoluble in water.
Sizes, Photographic. ■ The following tabular matter explains itself: -
Usual Sizes of French and Italian Dry Plates.