A Manual Of Photography

M. FLACHERON’s PROCESS. 233 will of course be understood by all who have followed the processes described up to this point, that the papers which are prepared for keeping are not those which are the most sensitive; hence it is necessary to expose such a much longer time in the camera than those prepared by the stronger solution of silver. The more sensitive variety, under ordinary circumstances of light, will require an exposure in the camera of about twenty seconds, the less sensitive demanding about 10 or 15 minutes, according to the circumstances of light. Fourth Process: The Development of the Image.—The picture is developed by the aid of gallic-acid dissolved in distilled water. Le Gray finds the following to be the best proportions :— Distilled water ................40 fluid ozs. Gallic acid ...........60 grains. The paper is to be plunged into this solution, and allowed to remain until it is fully developed. The time will vary from ten minutes to two hours or more, according to the intensity of the rays incident on the paper when in the camera. The develop- ment of the image is much accelerated by the addition of 15 or 20 drops of the aceto-nitrate of silver. Fifth Process : Fixing.—It is found convenient often, when on a journey, to give a temporary fixedness to the pictures obtained, and to complete the process with the hyposulphite at any time on your return home. A wash of 360 grains of bromide of potassium to two quarts of water is the strength whicli should be employed. The process of fixing with hypo- sulphite consists, as in other preparations, simply in soaking the paper until the yellow tint of the iodide has disappeared: the details are particularly given at page 216, in the chapter on Fixing Photographs. Section V.—M. Flacheron’s Process. The productions of M. Flacheren, which were seen in the Great Exhibition, excited much interest, and the process by which these were obtained in the Eternal City was eagerly sought for by photographic amateurs. In the Art Journal for May, Mr. Thomas has communicated the process by which the photographers of Home produce their best effects ; and as this is very important, as being useful in hot climates, a sufficient portion of that communication is transferred to these pages.