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" Recent Advances in Photography." 



Mr. Seymour Burrows, B.A. (Cantab.), M.R.C.S. 



Read April 6th, 1887. 



The author gave a resumd of the progress of Photography from 

 its commencement with Niepce, who found that light acted on a 

 thin layer of bitumen of Judsea, when spread on metallic plates 

 in such a manner, as to cause it to be insoluble in substances which 

 would otherwise dissolve it. The next important step was the 

 use of silver salts, in the form of choloride, on paper, by Davy and 

 Wedgwood. They could not, however, render the impressions 

 obtained permanent. To Daguerre belongs the merit of first 

 making a positive picture by photography. The impression was 

 received on iodide of silver developed by means of mercurial fumes 

 and fixed by hyposulphite of soda. This was in 1839. In 1841 

 Fox-Talbot invented the process which took his name. He used 

 iodide of silver paper and developed by gallo-nitrate of silver. 

 The parts acted on by light, then became black. This afforded a 

 negative by which he obtained prints. This held its ground till 

 1856, when Scott- Archer brought out the collodion process, which 

 was practiced till quite lately, when gelatine was found a better 

 medium for silver salts, and is now so much in vogue, as the dry 

 plate process, with its sensitiveness and wonderful rapidity. This 

 was an enormous advance on the slow and dirty wet processes 

 previously adopted. Mr. Eastman has comparatively re- 

 cently brought out paper coated with gelatine emulsion, 

 which is transparent, and on which negatives may be 

 taken. The advantage of this in the place of glass to tourists 

 and travellers, would be at once apparent. Mr. Burrows briefly 

 described the different processes of printing photogographically. 

 First the method on silver-paper then the platinotype process ; 

 also the use of gelatine covered paper, by means of which prints 

 may be readily obtained by candle-light. The purely mechanical 

 processes of printing were next explained, viz : those known as the 

 Helitype, Autotype, Woodburytype, Zincography, &c. The author 

 next alluded to the wonderful advances recently made in 



