r and now employed for the ornaments of
"articles de Paris:" Prepare the provisory support as usual, but with a
thicker film of collodion; then, after developing and coloring, if
necessary, the picture is coated with gelatine, to which may be added some
zinc white or other colored substance to form a ground. This dry, strip
off, immerse the pellicle in water to soften the gelatine and transfer on
the material collodion side up.

The proofs should be developed within three or four hours after
insolation, for the luminons action continues pretty actively in the dark,
and this for a long time; thus: a proof rightly exposed in the morning
behaves as one over-exposed if developed in the evening, and after a
certain period either can not be developed or refuses to adhere on the
support. However, the proofs can be kept for three weeks, may be more,
before development, if the soluble bichromate be washed off, the tissue
sponged and dried rapidly in the warm season. This capital improvement is
due to Mr. Charles Brasseur.

It has been said that before being applied on the support the proof should
be immersed in water to soften the tissue. The time which it should be
allowed to absorb water has an importance which must not be neglected. If
it do not remain long enough to be soaked through, small invisible air
bubbles are formed on its surface, and interposing themselves between the
image and the support, form minute, brilliant, silver-like spots on the
finished picture; and, if the temperature of the water is above 20 deg. C.
(68 deg. Fahr.), the image will be more or less reticulated. The
temperature depends a good deal of the softness of the gelatine; 15 deg.
C. (59 deg. Fahr.) is safe, except, however, when the thermometer is in
the thirtieths (90th Fahr.), when the water should be cooled down a few
degrees lower, but not at the melting ice temperature, for then the proof
would not adhere well. As a rule, the tissue should remain in the cold
water until it becomes flat and shows a tendency to curl up. It is at
this very moment that it should be squeezed on the support.

The proofs should not be developed immediately after transferring. The
adherence is greater and the pictures finer and devoid of defects when the
development is made half an hour, and even an hour, after. If developed
too soon the picture will be partly, and even entirely, washed off.
Hence, a number of transfers can be prepared beforehand, placing t