ACETONE (Fr., Acetone ; Ger., Aceton) A colourless volatile liquid of peculiar and characteristic odour, having the formula C3 0 or CO CH3. It is met with commercially in various qualities. It is miscible in all propor tions with water, alcohol, and ether. As the vapour is highly inflammable, the liquid should be kept in a bottle with a close-fitting cork or glass stopper. Acetone has two separate and distinct uses in photography, as an addition to developers and in varnish making. It acts as a solvent for resins, camphor, celluloid, etc., and should therefore never be used for films or in a celluloid dish.
As a constituent of a developer acetone works best perhaps with pyro in the following one solution form :— Pyro . . . . 18o grs. 18 g.
Sodium sulphite (crystals) 1,120 „ 112 „ Acetone . . . . 24 rains. ccs.
Water to . . . 20 OZ. 1,000 „ It may, however, be used with other developers.
When mixed with sulphite it forms acetone sulphite, and the soda of the sulphite combines with the developing agent to form a pheno late, so that it may be used in place of an alkali when sulphite is present. It gives a very dean-working developer, moderately free from stain, and hardens the gelatine, or at any rate does not soften it as alkalies do. As a developer for paper prints it is best when combined with metol-hydroquinone in the following form :— Metol . . 27 grs. 2.7 g.
Sodium sulphite • oz. ,, Hydroquinone . . 88 grs. 8.8 „ Potass. bromide (io %) 22 mins. 2•2 „ Acetone . . . 4o drms. 25 ccs.
Water to . • • 20 OZ. 1,000 „ This is a one-solution developer which, as above compounded, is ready for use for both plates and papers.