GELATINE EMULSION. C.
EDER.
| Bromide potassium | 4 | grams, equal to | 61 grains. |
| Gelatine | 7½ to 8 | grams, equal to | 115 grains. |
| Water | 50 | c. c., equal to | 1 ounce. |
| Nitrate of silver | 5 | grams, equal to | 77 grains. |
| Water | 50 | c. c., equal to | 1 ounce. |
Dissolve the silver in water and precipitate it with ammonia. Continue the addition a few drops at a time, until the brown oxide of silver re-dissolves and the liquid looks as bright as pure water; the strength of the ammonia is immaterial.
The nitrate of silver may be warmed to 93 degrees F., and poured into the bromized gelatine a little at a time, continually stirring with a glass rod. Rinse the silver bottle with 10 c. c. about 1½ drachms of water and add it to the emulsion, place the bottle containing the emulsion in a basin or saucepan of water heated to 90 degrees F., leave it therein from 15 to 30 minutes without further heat; after 30 minutes the emulsion is ready to be congealed previous to washing.
This emulsion never fogs, but it is imperative that p44 in no part of the progress the temperature should exceed 100 degrees F., and it is a safe rule not to go beyond 90 degrees F. It is recommended to use French gelatine.
GELATINE EMULSION. D.
EDER.
| Bromide of potassium | 61 grains. |
| Gelatine | 115 |
| Water | 1 oz. (plus) |
The bromide of potassium must be pure and not alkaline, ditto the gelatine.