150 THE PRODUCTION OF POSITIVES. 



the qualities before recommended will require a sub- 

 dued light and two or three hours exposure for the 

 differentiation of the markings and the proper repro- 

 duction of the tones existing in the original. Bright 

 sunlight must never be employed for silver printing 

 by contact. 



The depth of the print requires some practice to 

 determine. As a rule the printing must be carried 

 farther than will be necessary in the finished picture, 

 because it loses intensity in the subsequent toning 

 and fixing processes. These processes should not be 

 commenced until several prints have been taken, as 

 one print wastes as much solution and gives as much 

 trouble as a dozen. 



When a sufficient number have been printed, they 

 are placed in a large quantity of water in a darkened 

 room. The water is changed every hour or so until 

 all milkiness disappears, and they are then immersed 

 in a solution consisting of: 



Gold Trichloride, 4 grains. 

 Sodium Acetate, 108 grains. 

 Distilled water, 10 ounces. 



This solution is best made with boiling distilled 

 water if immediately required for use. It would be 

 better to make it the day before. 



A large flat dish will be found the most convenient 

 for holding the prints and solution, as they require 

 to be kept in continual motion during the process. 

 The tint must be deeper, and as in printing, the 

 process must be carried farther than is necessary 

 in the finished picture. A very deep chocolate 



