The chemist's compendium for pharmacists, chemists, and students / compiled by C.J.S. Thompson.

  • Charles Thompson
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: The chemist's compendium for pharmacists, chemists, and students / compiled by C.J.S. Thompson. Source: Wellcome Collection.

    205/260 (page 191)
    Solution No. 2. Silver Nitrate . . ] ounce. Distilled Water, to make . . 8 ounces. Directions for Use.—Lay the well-washed negative or bromido ■ print in No. 1 solution till bleached right through, well wash, and then immerse in solution No. 2 till it has darkened right i through, then wash, and place for a few minutes in a clean fixing ' bath, and again wash. Solution No. 1. Mercury Perchloride Hydrochloric Acid, pure Distilled Water, to make 100 grains. 30 mins. 10 ounces. Solution No. 2. Silver Nitrate Distilled Water, to make Potassium Cyanide 200 grains. 10 ounces, q.s. The proper method of making this solution is to dissolve the silver nitrato in 5 ounces of tho water and 200 grains of cyanide in about 1 ounce of distilled water, place tho silver solution in the bottle, and add the cyanide in quantities of about 1 drachm at a time, shaking thoroughly after each addition. A curdy white precipitate will bo formed, and as more cyanide is added this will gradually re-dissolve. Care must be taken that all the silver cyauido is not re-dissolved ; some undissolved pre- cipitate must be present, or else this solution will attack the image. Platinum Toning Batiis. (For Chloride Papers.) Liquid Bath. Potassium Cliloroplatinite ... 30 grains. Lactic Acid (S.G. 1*21) .... 155 mins. Distilled Water . . . . .10 ounces. Directions for Use.—Dilute this solution with double its volume of water before use.