SCIOPTICON MANUAL. 75 



portrait negatives. There seems no reason why enlarge- 

 ments made in this way, for ornamental transparencies, 

 to be hung in the window, or set in a frame, should not 

 become a profitable branch of photography. 



The toning of glass positives, to be used for orna- 

 mental purposes, involves some thought as to the par- 

 ticular color, or shade of color, that will suit the picture 

 best; and it is impossible to give one process that will 

 suit all tastes alike; some having a preference for black 

 tones, others for blue-black, brown, or the various shades 

 of gray. A detailed description of the manner of pro- 

 ducing these various tones would require too much space, 

 and is so simple that no one can go astray. 



The principal chemicals required are : Chloride of 

 gold, bichloride of platinum, bichloride of palladium, 

 sulphide of potassium, and permanganate of potassium; 

 in all cases use singly and very dilute. I am disposed 

 to consider chloride of palladium as the most reliable 

 chemical that has come under my notice. Its action is 

 perfectly manageable, easy to prepare, will not stain, 

 and gives uniformly good results. The toning solution 

 that I use is made as follows : Add six drops from the 

 stock-bottle of chloride of palladium to each ounce of 

 water; this solution should be of a delicate straw color. 

 No other manipulation is required. After the plate has 

 been developed and fixed, wash as usual, then apply the 

 toning solution by flowing it over the plate similarly to 

 the developer. Its action will be quick, giving a black 

 tone to the positive. Wash well, dry, and varnish if 

 desirable. 



Thcso transparencies are covered and bound with an 

 opal or ground-glass, or they may be flowed with a var- 

 nish containing a little fine zinc paint, ground in varnish. 



It may bo mentioned in this connection, that artists 



