This is a more rapid developer than the preceding. The print is
fixed in like manner by water, in which it must be well washed, and
afterwards dried. When dried by artificial heat, the vigor of the
print is increased. [p211] Prints that have been developed by the
solution of nitrate of silver may be immersed in the gold bath,
which improves their tone.
The picture may be developed, also, by immersing the prints in a
saturated solution of bichloride of mercury and afterwards in one of
nitrate of silver. In this case, however, the times of exposure must
be increased.
Pictures may be obtained, also, by floating the papers on a mixture
of equal quantities of nitrate of silver and nitrate of uranium in
about six times their weight of water.
When dry, they are exposed beneath a negative. In this case the
image appears, as in the positive printing process, with chloride of
silver, being effected by the decomposition of the nitrate of
uranium, which, reacting on the nitrate of silver, decomposes this
salt and reduces the silver. These prints require fixing in the
ordinary bath of hyposulphite of soda, and then washing, as usual.