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Various

"Scientific American Supplement, No. 623, December 10, 1887"


I will now take up a negative in this state on the glass, but dry, and
carefully cut round the edges of the film, and you see I can readily
pull off the film with its gelatine support. Having now passed through
the whole of the process, it behooves us to consider for a few minutes
the causes of failure in the hands of beginners and their remedies: 1.
The rubber will not flow over glass? Solution too thick, glass greasy.
2. Rubber peels off on drying? Dirty glass. 3. Negative not dense
enough? Use more bromide and longer development. 4. Gelatine cracks on
being pulled off? Add more glycerine. 5. Gelatine not thick enough?
Gelatine varnish too thin, not strong enough. 6. Does not dry
sufficiently hard? Too much glycerine.--_E.H. Jaques, Reported in Br.
Jour. of Photography._
* * * * *


HOW DIFFERENT TONES IN GELATINO-CHLORIDE PRINTS MAY BE VARIED BY
DEVELOPERS.

The following formulae are for use with gelatino-chloride paper or
plates. The quantities are in each case calculated for one ounce,
three parts of each of the following solutions being employed and
added to one part of solution of protosulphate of iron. Strength, 140
grains to the ounce.
_Slaty Blue._
1.


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