Art of Photogenic Dra'wing. 207 



ing the prepared paper. In this way I have obtained images 

 of" various statues, &c. I have not pursued this branch of the 

 subject to any extent; but I expect interesting results from it, 

 and that it may be usefully employed under many circum- 

 stances. 



§ 11. Ccpying of Engravings. 



The invention may be employed with great facility for ob- 

 taining copies of drawings or engravings, or facsimiles of 

 MSS. For this purpose die engraving is pressed upon the 

 prepared paper, with its engraved side in contact with the 

 latter. The pressure must be as uniform as possible, that 

 the contact may be perfect ; for the least interval sensibly in- 

 jures the result, by producing a kind of cloudiness in lieu of 

 the sharp strokes of the original. 



When placed in the sun, the solar light gradually traverses 

 the paper, except in those places where it is prevented from 

 doing so by the opake lines of the engraving. It therefore of 

 course makes an exact image or print of the design. This is 

 one of the experiments which Davy and Wedgwood state that 

 they tried, but failed, from want of sufficient sensibility in 

 their paper. 



The length of time requisite for effecting the copy depends 

 on the thickness of the paper on which the engraving has 

 been printed. At first I thought that it would not be possi- 

 ble to succeed with thick papers ; but I found on trial that 

 the success of the method was by no means so limited. It is 

 enough for the purpose, if the paper allows any of the solar 

 light to pass. When the paper is thick, I allow half an hour 

 for the formation of a good copy. In this way I have copied 

 very minute, complicated, and delicate engravings, crowded 

 with figures of small size, which were rendered with great di- 

 stinctness. 



The effect of the copy, though of course unlike the original, 

 (substituting as it does lights for shadows, and vice versa,) yet 

 is often very pleasing, and would, I think, suggest to artists 

 useful ideas respecting light and shade. 



It may be supposed that the engraving would be soiled or 

 injured by being thus pressed against the prepared paper. 

 There is not much danger of this, provided both are perfectly 

 dry. It may be well to mention, however, that in case any 

 stain should be perceived on the engraving, it may be readily 

 removed by a chemical application which does no injury 

 whatever to the paper. 



In copying engravings, &c. by this method, the lights and 

 shadows arc reversed, consequently the effect is wholly al- 

 tered. But if the picture so obtained is fiirst I'^'^scrved so as 



