76 Paper Process in Photography. [no. 1, new series, 



paper with a fresh piece on the top, on this lay the wet side of 

 your paper, and cover it with another piece of fresh blotting paper 

 — blot off the excess of fluid by passing the hand lightly and 

 equally over it. Then put in between fresh blotting paper and 

 place it in a drawing paper envelope, which may be deposited in 

 a portfolio or a flat tin case made for the purpose, until required 

 to be put in the slide. This should not be done for about half an 

 hour, unless it be intended to expose it immediately, as the eva- 

 poration from the paper is condensed upon the glass, and forms a 

 number of small plano-convex lenses which doubtless refract the 

 rays that have passed through the glass of the slide and injure the 

 picture. 



I have not had occasion to keep this paper longer than 18 hours 

 after exciting, it kept well for that time. 



Exposure in the Cameea. 



With a given paper and light, the time of exposure will depend 

 upon the focal length of the lens, and the aperture of the dia- 

 phragm in front of it. My pictures were taken with a Ross' 4 inch 

 Landscape lens of 20 inches focus, with an aperture of \ an inch 

 in the diaphragm. And the time of exposure I found necessary 

 will be the best guide I can give to others. 



I took a good negative of the Catholic Cathedral in 9 minutes, 

 between 3 and 4 p. m., the paper having been excited about half 

 an hour previous to exposure in the Camera. This is a white 

 building much darkened by time. There were some deep shadows, 

 the detail in which is fairly rendered: the Cassarina trees also 

 would have been tolerably well represented, had it not blown very 

 hard at the time. During half the time of exposure, the sun was 

 obscured by a small, but dense, black cloud. The Museum was 

 taken between 7 and 8 a. m. on paper excited on the previous even- 

 ing, it was exposed 9 minutes in bright sunshine. This was per- 

 haps exposed rather too long to be called a good negative, al- 

 though not altogether to be despised. It need not have been made 

 quite so intense, but there was a palankeen carriage and horse in 

 very deep shadow under a large tree, which I wished to bring out, 

 or else the development could have been stayed earlier. These 



