hem,
face to face one upon another, in order that the tissue does not dry,
which is quite essential.

To develop, the plate, with the tissue adhering to it, is placed in water
heated to 30 deg. C. (80 deg. Fahr.), where it is left rocking the tray
occasionally until the paper rises up by itself at the corners, when
taking hold of it by one corner, it is stripped off, leaving behind the
image buried in soluble gelatine. Should the paper offer any resistance
whatever, the gelatine should be allowed to become more soluble by
increasing the temperature of the water, or by a longer immersion. There
is, in fact, no objection to this. The plate--and that is a good
method--can be placed in an upright position in a tin box, made ad hoc, and
left therein in warm water until the paper detaches itself and the image
is partly developed _and the bichromate washed off._ This done, the plate
is held in an inclined position on a tray filled with water at 35 deg. C.
(95 deg. Fahr.), which is dashed with a wooden spoon on the image to clear
it from the non-acted-on gelatine. Presently one can judge whether the
exposure is right. If it is too short, the half tints in the shadows are
washed off, unless the negative be too intense, when a similar effect also
occurs in the whites. If it is too long, either the image is with
difficulty cleared or remains undeveloped. In the latter case, it is
recommended by some operators to increase the temperature of the
developing water to near the boiling point, and, for local clearing, to
pour it on. This we find objectionable, for the half tints are easily
washed off. A better process, when the picture can not be cleared by
water at 50 deg. (122 deg. Fahr.), or thereabout, is to use a solution of
common salt at 5 or 6 per cent. of slightly warm water.(31) It is even
preferable to finish the development in a tepid solution of potassium
sulpho-cyanide, 12:100. The dissolving action is long, but not only, as
said above, the half tints are best preserved, but blistering and local
washing-off are avoided.

After development the plate is rinsed under the tap, then flowed two or
three times with a solution of chrome alum at 1 per cent. of water, then
washed, and finally allowed to dry spontaneously.

It is objectionable to use a strong solution of alum, and in it to immerse
the plate for any length of time; the gelatine is considerably
hardened--which is not necessary--and more liable to crack by