344 Mr. T, A. Malone, on the Application of Light [Feb. 13, 



Thejirst method, in which light was used to aid the engraver's art 

 was almost coeval with the first attempts made to produce sun-drawn 

 pictures. Indeed it had been asserted that photography and photo- 

 graphic engraving were invented between the years 1813 and 1827, 

 by one man, Nicephore Niepce, of Chalon on the Saune. A 

 reference, however, to the Journal of the Royal Institution* would 

 show that photography really sprang from the labours of Thomas 

 "Wedgwood and Humphry Davy, as far back as the year 1802, 



Although we cannot accord to Nicephore Niepce the merit of 

 originating photography, we must give him the undivided title of 

 founder of the art of photographic engraving, and, moreover, 

 acknowledge that he was the first to fix not only a direct positive 

 photograph, but also to secure on metal and glass plates the images 

 of the camera, and this long before Daguerre produced his won- 

 derful plates. Of this there can remain no doubt, after a study of 

 the remarkable specimens which Dr. Robert Brown has so kindly 

 enabled photographers now for the first time publicly to examine. 

 It was not generally known that Niepce's images of 1827 had so 

 much that is beautiful, in common with the daguerreotype of a later 

 date. Daguerre's pictures may be said to be only exalted exampltes 

 of the same phenomenon : yet the processes are widely different. 

 Niepce's method was beautifully simple, and as it gives us the 

 ground-work of his etching process, must be briefly described. He 

 took a bituminous substance called Jew's pitch or asphaltum ; upon 

 this he poured oil of lavender to resolve the bitumen into a varnish 

 with which he could coat plates of metal or glass. He used chiefly 

 pewter and copper plated with silver. A plate coated and dried 

 was exposed to the light with an engraving superimposed, or it was 

 placed in the field of the camera obscura just as Wedgwood and 

 Davy placed their prepared papers ; and with a certain similarity of 

 result, inasmuch as a photographic image was obtained on the var- 

 nished plate. This image, however, unlike that of Wedgwood and 

 Davy, was not visible. The plate had to be submitted to the solvent 

 action of a mixed liquid, composed of one part of oil of lavender 

 and ten parts by measure of white oil of petroleum^ or mineral 

 naphtha. On immersion in this fluid the remarkable fact revealed 

 itself, that wherever the light had acted the varnish had become 

 insoluble, and in a certain degree proportionately so to the intensity 

 of the light. There were not only lights and shadows but half 

 tints. The picture, as soon as developed by the solvent, was re- 

 moved, drained, and washed with water to check all further action. 

 The shadows of the picture were now represented by the parts of 

 the white metal, or glass plate laid bare ; the lights were given by 

 the film of varnish which the light had hardened, and the solvent 

 had left untouched. The plate now finished was capable of being 

 etched by simply pouring engraver's acid upon its surface. The 



♦ Journal of the Royal Institution, Vol. I. p. 170. 



