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Various

"Scientific American Supplement, No. 401, September 8, 1883"


Made slightly acid with nitric acid.
After sensitizing, the plate is exposed in the usual way and taken to
the room where pictures are ordinarily developed, and _quantum suff_. of
the following poured into the developing cup to bring out the image:
DEVELOPING SOLUTION.
A Winchester of water, i.e. 80 ounces.
Protosulphate of iron. 240 grains.
Citric acid. 240 "
Or the following may be used:
Pyro 3 grains\
Citric acid 2 " } per ounce of water.
Glacial acetic acid 30 drops /
After perfect development the picture is well washed and then fixed in a
saturated solution of hypo.; after which it is thoroughly washed.
It will now be found that the picture is not altogether satisfactory; it
lacks both vigor and color. To improve matters recourse is now had to

TONING.
Gold. 1 grain.
Water. 5 ounces.
With this a very fine depth is soon attained, and a nice picture the
result. Leave out the toning, and only a poor, sunken-looking picture
will be the outcome; but directly the toning bath is employed richness
at once comes to the fore.


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