LIPPMANN'S PROCESS A process of colour photography in which the phenomenon of stationary or standing waves is utilised. The process consists in exposing a transparent emulsion in contact with a reflecting surface, such as mercury. Prof. Gabriel Lipp mann first used Taupenot's albumen process, and Krone, who has been extremely successful with this process, gives the following method : Albumen from whites of 6 eggs. . . 4 oz. 130 ccs.
Pot, bromide (xo % sol.) 51 mins. 4'3 ), Liq. ammonite (strongest) 51 ,, Beat to a froth, and allow to stand for twelve hours to liquefy, and then carefully decant or filter through some glass-wool. Unused glass plates should be thoroughly cleaned with alcohol, and then evenly coated with the above and drained, allowing them to dry in a hori zontal position. When thoroughly dry they should be heated to 14o° F. for two minutes, and then allowed to cool down to normal temper ature and sensitised by bathing for two minutes in a io per cent. solution of silver nitrate acidu lated with xo per cent. of glacial acetic acid. The plates should next be washed for ten min utes and rinsed with distilled water, well urained, and colour-sensitised in one of the following baths : A. Chinoline red sol.
(1 :50o) . . 27 mins. 1.6 ccs.
Cyanine sol. (I :50o) 7 4 cc.
Ammonia (2 % sol.) 50 3 ccs.
Distilled water to . 7 oz. 200 B. Erythrosine sol.
(1 : 500) . . 17 mins. x cc.
Cyanine sol. (1 : 500) 17 Ammonia sol. (2 %) 51 3 ccs.
Distilled water to 7 oz. zoo C. Chinoline red sol.
(1 :500) . . 25 mins. 1.5 ccs.
Malachite green sol.
(1 : 500) . . 5 cc.
Ammonia sol. (2 %) 51 3 ccs.
Distilled water to 7 oz. 200 D. Erythrosine sol.
: 500) . . 17 mins. 1 cc.
Malachite green sol.
(1 : 500) . . 17 Ammonia sol. (2 %) 51 3 ccs.
Distilled water to 7 oz. 200 The plates should be bathed for three minutes in absolute darkness, allowed to drain for a minute or two, and then dried at 14o° F. (6o° C.). For normal work A is to be preferred, but with decreasing height of the sun B or D is better. The developer recommended is A. To per cent. alcoholic solution of pyro.
B. Ammon. carbonate 772 grs. 5o g. Distilled water to xo oz. 268 mins. 30o ccs.
C. xo per cent. solution potassium bromide.
For a 7 x 5 (13 x 18 cm.) plate, mix freshly of A . . . . 128 mins. 7'5 ccs.
B ,, 20 C . . . . drops 15 drops Distilled water 1 oz. 27 mins. 3o ccs.
When developed, wash and fix in a 1.5 solution of " hypo," and if the plate appears too thin, intensify with acid pyro and silver intensifier.
Valenta was the first to publish a gelatine emulsion formula : A. Distilled water bo oz. 268 mins. 30o ccs. Gelatine . . 154 grs bo g.
Silver nitrate . 93 6 B. Distilled water bo oz. 268 mins. 30o ccs. Gelatine . . 309 grs. 20 g.
Potassium bromide 77 5 Heat both solutions to 95* P. (35° C.) and add A slowly to B with vigorous agitation. Valenta recommends pouring the emulsion immediately into 35 oz. or x litre of alcohol, stirring well with a glass rod and then washing for a short time in running water the precipitated emulsion, next placing in a vessel and adding enough water to make 21 oz. or 600 ccs., melting at as low a temperature as possible, filtering and coating the emulsion. Later he suggested coat ing the plates without washing the emulsion, and washing the plates when the emulsion had set. The sensitiser used was : Cyanine sol. (x : 500) 68 mins. 4 ccs.
Erythrosine sol. (I : 50o) 34 ), 2 and x to 2 parts of this were added to every boo parts of the emulsion. Increase of sensitiveness was obtained by bathing the plates just before use in : Silver nitrate . . 48 grs. 5 g.
Glacial acetic acid . 48 mins. 5 ccs.
Alcohol . . . 20 OZ. I,000 Valenta also stated that the addition of 3x grs. or 2 g. of sodium sulphite to the above quantity of emulsion, and digestion for a short time, in creased the sensitiveness without increasing the size of the grain.
Messrs. Lumiere in 1893 published their method of making the emulsion, and valuable contributions also came from Valenta, Neu hauss, and Senior. The last named specially recommends the following : A. Nelson's No. 1 gela tine . . 77.15 grs. 5 g.