90 



Let well-glazed paper (I prefer that called wove post) 

 be steeped in water to which hydrochloric acid has been added 

 in the proportion of two drops to three ounces. When well wet, 

 let it be washed over with a mixture of syrup of ioduret of iron 

 half a drachm, water two drachms and a half, tincture of 

 iodine one drop. When this has remained on the paper for a 

 few minutes, so as to be imbibed, dry it lightly with bibulous 

 paper, and being removed to a dark room, let it be washed 

 over evenly, by means of a camel-hair pencil, with a solution 

 of nitrate of silver, ten grains to the ounce of distilled water. 

 The paper is now ready for the camera. The sooner it is 

 used the better ; as when the ingredients are not rightly mixed, 

 it is liable to spoil by keeping. The time I generally allow 

 the paper to be exposed in the camera varies from two to 

 thirty seconds ; in clear weather, without sunshine, the me- 

 dium is about fifteen seconds. With a bright light, the pic- 

 ture obtained is of a rich brown colour ; with a faint light, or a 

 bright light for a very short time continued, it is black. For 

 portraits out of doors, in the shade on a clear day, the time 

 for sitting is from ten to fifteen seconds. If the light is strong, 

 and the view to be taken extensive, the operator should be 

 cautious not to leave the paper exposed for a longer period 

 than five or six seconds, as the picture will appear confused 

 from all the parts being equally acted on. In all cases, the 

 shorter the time in which the picture is taken the better. 



When the paper is removed from the camera no picture 

 is visible. However, when left in the dark, without any other 

 preparation being used, for a period which varies with the 

 length of time it was exposed and the strength of the light, a 

 negative picture becomes gradually developed, until it arrives 

 at a state of perfection which is not attained, I think, by 

 photography produced by any other process.* It would seem 



* The picture, when developed, is not readily injured by exposure to mode- 

 rate light; it ought, however, to be fixed, which may be done by washing it 

 with a solution of bromide of potassium, fifteen or twenty grains to the ounce, 

 or iodide of potassium, five grains to the ounce. It may either be applied with 



