A Manual Of Photography

CHLORIDE OF SILVER. 207 Murlated Papers, as they are termed, are formed by producing a chloride of silver on their surface, by washing the paper with the solution of muriate of soda, or any other muriate, when the paper is dry, with the silver solution. It is a very instructive practice to prepare small quantities of solutions of common salt and nitrate of silver of different strengths, to cover slips of paper with them in various ways, and then to expose them altogether to the same radiations. A curious variety in the degrees of sensibility, and in the intensity of colour, will be detected, showing the importance of a very close attention to proportions, and also to the mode of manipulating. A knowledge of these preliminary but important points having been obtained, the preparation of the paper should be proceeded with ; and the following method is recommended:— Taking some flat deal boards, perfectly clean, pin upon them, by their four corners, the paper to be prepared; observing the two sides of the paper, and selecting that side to receive the preparation which presents the hardest and most uniform surface. Then, dipping one of the sponge brushes into the solution of muriate of soda, a sufficient quantity is taken up by it to moisten the surface of the paper without any hard rubbing; and this is to be applied with great regularity. The papers being “ salted," are allowed to dry. A great number of these may be prepared at a time, and kept in a portfolio for use. To render these sensitive, the papers being pinned on the boards, or carefully laid upon folds of white blotting paper, are to be washed over with the nitrate of silver, applied by means of a camel-hair pencil, observing the instructions previously given as to the method of moving the brush upon the paper. After the first wash is applied, the paper is to be dried, and then subjected to a second application of the silver solution. Thus prepared, it will be sufficiently sensitive for all purposes of copying by application. The second wash is applied for the purpose of ensuring an excess of the nitrate of silver in combination, or, more properly speaking, mixed witli tlie chloride. n o AT Mr. Cooper, with a view to the production of an uni- form paper, recommends that it be soaked for a con- siderable length of time in the saline wash, and, after '- ......... it is dried, that the sheet go should, by an assistant, be dipped into the silver solution ; while the operator moves over