Acid Hydrochloric

HC1 - IV, 552. Muriatic Acid or Spirits of Salt. Clear, colorless, pungent, fuming liquid; strongly acid; unpleasant smell. Should be kept in a glass stoppered bottle. In its impure form it is yellow in color - should be used only for cleaning dishes. In making up solutions use only the colorless, chemically pure liquid. Poisonous. Antidote: bicarbonate of soda and water. In case of an emergency, scrape ordinary plaster from the wall and mix with water. Used principally for clearing platinum prints, or freeing them of the iron salts. Citric acid may be substituted, but is more expensive.

Acid Hydrofluoric

HF - II.

Colorless, or almost colorless, mobile, fuming, corrosive liquid. Poisonous. It attacks almost everything, especially glass. Therefore, must be kept in glazed dishes. Use in lead or gutta-percha dishes. Used principally for stripping negatives, as it attacks the glass underneath the film, thus loosening the latter sufficiently to enable its being removed.

Acid Nitric

HNO3 - II, 46.

Transparent, colorless, fuming, suffocating, caustic, corrosive liquid; strongly acid. Must be kept in glass-stoppered bottles. Poisonous Antidote same as for acid hydrochloric. Used as a preservative for pyro in solution; in some reducing formula; in dissolving metallic silver; to make silver nitrate, etc.

Acid Oxalic

H2C2O4 + 2H2O.

Colorless, odorless, crystals; very acid taste. Soluble in 10 parts cold, 3 parts boiling, water; 2.5 parts alcohol; about 100 parts ether. Keeps well in corked bottle. Poisonous. Used in platinum process to acidify developing solutions; also in preparation of platinum emulsions. May be used to remove ink stains.

Acid Phosphoric

H3PO4 - IV, 151.

Transparent, deliquescent, colorless prisms; odorless; very acid taste. Poisonous and corrosive. Used in making up platinum toning bath for printing-out and salted papers.

Acid Picric

C6H3N3O - VII, 705.

Yellow, lustrous crystals; odorless; intensely bitter. Soluble in 10 parts alcohol, 6.5 parts ether, 170 parts water. Poisonous. Used for staining yellow screens, etc.

Acid Pyrogallic

C6H6O3 - II. Pyrogallol, or Pyro. Light, feathery, snow-like crystals; bitter. Poisonous. Soluble in 1.6 parts water, 1 part alcohol, and 1.1 parts ether. Very soluble in boiling water and boiling alcohol. The most widely used developer for dry plates. In its dry form keeps almost indefinitely. So long as it is white it has not deteriorated. Does not keep well in solution. If solution is acid it may be kept a few months, if in well-stoppered bottles, but an alkaline solution spoils in an hour, or less. For this reason always acidify the water before adding the pyro.

Acid Salicylic


Light, fine, white crystalline powder; sweet taste and acrid after-taste. Soluble in 2 parts ether, 2.4 parts alcohol, 60 parts glycerin, 80 parts chloroform, 450 parts water, 14 parts boiling water. It is frequently used as an antiseptic and antiputrefactive agent. Used as a preservative. Added to a gelatin or starchy mountant to preserve it.