CAMERA AND PHOTOGRAPHIC APPLIANCES 41 



be for a moment only but for the altogether. 

 So perfect is this backing in practice that I 

 have exposed a plate thus protected directly 

 facing several windows, outside of which the 

 sun was shining brilliantly, for several minutes 

 without the slightest trace of halation appear- 

 ing in the negative on being developed. In 

 preparing the paper for use I lay a sheet 

 slightly smaller than the plate upon a clean 

 table, pour a small quantity of glycerine in 

 the middle and spread it evenly over the sur- 

 face with a finger, using a liberal quantity, but 

 not too much. Then place it on the back of 

 plate and squeegee into optical contact. Strip 

 off before development. The paper may be 

 used repeatedly, adding a little fresh glycerine 

 each time. Try this. You will use no other 

 backing ever after. 



