14 de Setembro
THE LITERARY GAZETTE AND JOURNAL OF BELLES LETTRES, ARTS, SCIENCES
London, Saturday, september, 14, 1839
Academy of science, sitting of August 26.
M. Arago communicated to the Academy the result of some researches, made by M. Dumas, with the view of preserving the impression of the Daguerrotype.the varnish used by that celebrated chemist, and found to suceedbetter than any other, is composed of one part of dextrine to five of water, and is applied hot to the plate. The photogenic impression is thus free from any danger of friction, and may be copied by means of transparent paper, &c.; it, however, loses a good deal of its brilliancy. The varnish may be washed off again with hot water, without the photogenic impression receiving any damage, and the original brilliancy and distinctness of the image isthus restored to it. This statement of M. Dumas, was replied by M. Sylvester, who shewed thst he had long ago used the same vernish himself, and he recommended in its place the following composition: - Dextrine two parts, water six parts, and alcohol one part. He considered it doubtful whether these varnishes, if suffered to remain for any great length of time on the photogenic image, might not in the end injure and alter the chemical combination by which it is formed. It was hinted by M. Arago, that either the cooper sheet on which the plating of silver was made might br indefinitely reduced in thickness, or even that paper plated with silver might be employed. M. Chevalier, optician in the Palais Royal, making use of M. Daguerre’s method, has succeeded in getting some very fine photogenic drawings. M. Susse, picture-dealer, Place de la Bourse, has advertised Daguerrotypes for sale. The crowd at Giroux’s shop is immense, to see the photogenic apparatus and the impressions obtained by M. Daguerre himself. The unscientific are disappointed at the slate-coloured effect of the image, and many more at the price (about 400 francs) of the apparatus !!