138 THE PRODUCTION OF POSITIVES, ETC. 



negative, while one possessing the qualities before 

 recommended will require a subdued light and two 

 or three hours exposure for the differentiation of the 

 markings and the proper reproduction of the tones 

 existing in the original. Bright sunlight must never 

 be employed for silver printing by contact. 



The depth of the print re mires 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 uses 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, gr. iv. 

 Sodium Acetate, gr. cviii. 

 Distilled water, § x. 



This solution is best made with boiling distilled 

 water if immediately required for use. We prefer to 

 make it the day before. 



A large flat dish will be found the most con- 

 venient 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 



