A Manual Of Photography

Talbot’s instantaneous process. 33 rendering it much harder, and insoluble in liquids which dis- solved it previously. 4. AV ash with distilled water to remove any superfluous por- tion. of the nitrate of silver. Then give the plate a second coating of albumen similar to the first, but in drying avoid heating it too much, which would cause a commencement of decomposition of the silver. 5. To an aqueous solution of proto-iodide of iron addy?rs£ an equal volume of acetic acid, and then ten volumes of alcohol. Allow the mixture to repose two or three days. At the end of mat 111116 if will have changed colour, and the odour of acetic acid as well as that of alcohol will have disappeared, and the liquid will have acquired a peculiar but agreeable vinous odour. It is in this state that I prefer to employ it. Into the iodide thus prepared and modified the plate is dipped for a few seconds. All these operations may be per- formed by moderate daylight, avoiding, however, the direct solar rays. 7. A solution is made of nitrate of silver, containing about grains to one ounce of water. To three parts of this add two of acetic acid. Then, if the prepared plate is rapidly dipped once or twice into this solution, it acquires a very great degree of sensibility, and it ought then to be placed in the camera without much delay. AThe plate is withdrawn from the camera, and in order to bring out the image it is dipped into a solution of protosulphate of iron, containing one part of the saturated solution diluted with two or three parts of water. The image appears very rapidly.r 9. Having washed the plate with water it is now placed in a solution of hyposulphite of soda, which in one minute causes the image to brighten up exceedingly, by removing a kind of veil which previously covered it. 10. The plate is then washed with distilled water, and the process is terminated. In order, however, to guard against future accidents, it is well to give the picture another coating Oi albumen and of varnish. “These operations may appear long in the description, but they are rapidly enough executed after a little practice. In the process which 1 have now described, I trust that I have effected uharmonious combination of several previously ascertained and valuable facts, especially of the photographic property of iodide 'f iron, which was discovered by Dr. Woods, of Parsonstown in Ireland ; and that of sulphate of iron, for which science is in- (eoted to the researches of Alr. Robert Hunt. In the true n