Bayswater.
_Developing Paper Pictures with Pyrogallic Acid_ (Vol. vii., p.
117.).--Your correspondent R. J. F. asks if any of your photographic
correspondents have developed their paper negatives with pyrogallic acid. I
have long been in the habit of doing so by the following process. Of Mr.
Archer's developing solution, viz.,
Pyrogallic acid 3 grs.
Acetic acid 1 drachm.
Distilled water 1 oz.
take twenty grs. (minims): add an equal quantity of distilled water, and
five drops (minims) of acetic acid. I pour the mixture upon a glass plate,
and put the sensitive surface of any picture upon it; moving, it up and
down by one corner, to prevent the paper being stained, and to observe the
development of the picture; which, when sufficiently come out, I blot and
wash immediately, and fix with hyposulphite of soda or bromide of
potassium.