PRINTING ON GELATINO-CHLORIDE PAPER. 
135 
downwards in the same water, bring the two up 
together, excluding air-bubbles ; lay the two down, 
paper upward; over the paper lay a piece of india- 
rubber or American cloth, cloth side downwards, and 
pass the squeegee briskly, but not heavily, over the 
cloth in both directions. Let the print dry gradually, 
and finally strip it from the plate. To give a print 
strength, if desired, it may be backed while wet and on 
the plate with a piece of very thin card, the print being 
backed with thin glue or starch. 
Prints should always be treated with alum if they are 
to be squeegeed to glass or ferrotype. 
If it is intended to mount prints on card, retaining 
the high gloss, the prints, while wet and adhering to the 
ferrotype or glass plate, should be backed with a piece 
of backing paper, which is impervious to water. This 
paper may be caused to adhere by a starch mountant, 
or, better, by a thin well-filtered solution of glue. This 
solution is used to cause the backing paper to adhere 
first to the print, and later to the permanent mount. 
Printing on “Gas-light” Papers. Black Tones. 
A certain class of printing paper has lately come 
very much into vogue, and as when properly treated it 
yields results almost ideal for our purpose, and that 
with a simplicity and certainty greater than, perhaps, 
any other process, we shall give explicit directions for 
its use. The emulsion is of such a nature that while 
it can be “exposed” by a strong artificial light, it can be 
developed in safety by a naked but fainter light. The 
exposure may be made for a few minutes about six inches 
