On reading the above again, fearing lest any misconception should arise in the mind of the reader, I deem it expedient, to clearly state that for terra-cotta recourse is had to double transfer; that is, the picture first taken is lifted from the support on tracing paper, put in the right position on terra-cotta, and pressed down while wet with blotting-paper, left to dry, and is then so far ready.
Respecting the production of pictures by means of emulsion, ground opal being the best, the system I employ is as follows: After well cleaning the glass, coat it with emulsion (which had better not be too thick). When dry it is exposed and developed with the usual oxalate developer, to which a little bromide of potassium has been added. The remainder of the operations is as usual. Those varnished with dead varnish can be tinted and worked up with colored crayons or black lead pencil and make very pleasing pictures. It is needless to add that they are also to be finished in water-colors if thought preferable.--G. W. Martyn, in Br. Jour. Photo.
PAPER NEGATIVES.
The process of A.C.A. Thiebaut is as follows: the paper has the following advantages:
First. The sensitive coating is regular, and its thickness is uniform throughout the entire surface of each sheet.
Second. It can be exposed for a luminous impression in any kind of slide as usually constructed.
Third. It can be developed and fixed as easily as a negative on glass.
Fourth. The negative obtained dries quite flat on blotting paper.