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Various

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

Second, they are
a little more trouble to finish than the glass negatives, which sink
into insignificance when the manifold advantages are considered.
In order to deal effectively with the second objection I mentioned,
viz., the extra trouble and perseverance, I propose, with your
permission, to carry a negative through the different stages from
exposure to completion, and in so doing I shall endeavor to make the
process clear to you, and hope to enlist your attention.
The developer I use is slightly different to that of the Eastman
company, and is as follows:
A.
Sulphite of soda. 4 ounces.
To be dissolved in 8 ounces of hot distilled water, then rendered
slightly acid with citric acid, then add--
Pyrogallic acid. 1 ounce.
Water to make up to 10 ounces.
B.
Pure carbonate of soda. 1 ounce.
Water to make up in all to 10 ounces.
C.
Pure carbonate of potash. 1 ounce.
Water to make up to 10 ounces.
D.
Bromide of potassium. 1 ounce.
Water to make up to 10 ounces.
I have here two half-plate films exposed at 8:30 A.M. to-day, one with
five and one with six seconds' exposure, subject chiefly middle
distance.


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