On a neio Photo-Lithographic Process. 181 



gelatine which is first struck by the luminous rays ; namely, 

 that surface which is in contact with the negative, and the 

 lines and dots forming the picture are bounded by a section 

 made through that surface, and not through that which is in 

 contact with the stone, or otjier material on which the gela- 

 tine is spread, whereby I produce the utmost sharpness of 

 definition. 



6th. I can prepare a stock of sensitive gelatinous papers, 

 which will keep for a considerable time^ready for use at any 

 moment; whereas when stones are used they must be 

 severally prepared when wanted. 



7th. One most important peculiarity in which my process 

 surpasses all others is involved in my method of inking. 

 Other operators (M. Poitevin for example) who have used gela- 

 tine, after having exposed the sensitive surface, proceed by 

 wetting it before applying the ink, with a view to keep the 

 unaltered portions free from ink; the consequence of which is 

 a part of the gelatinised surface is rubbed over the altered parts 

 which represent the drawing, making them refuse to take the 

 ink, or only to do so with difficulty ; and the quality of the 

 ink, and by consequence that of the lithograph, is very much 

 injured; whereas I ink-in, covering the whole surface of the 

 photographic print while dry, before the swelling of the un- 

 altered gelatine has depressed the positive portions of the 

 print, and trust to the subsequent washing processes to re- 

 move the gelatine, and with it the ink from those parts which 

 ought to be clean and white. 



8th. The method I have adopted of applying the ink in 

 the press cannot I believe, be surpassed; it gives the greatest 

 regularity and accuracy as to quantity, and aids the affinity 

 which exists between the altered gelatine and the ink, by the 

 force with which it is applied. 



9th. The coating of albumen on the paper which precedes 

 that which I apply of gelatine, is also of the greatest value, 

 and its adoption is completely original. The solubility of 

 dried albumen causes the albuminised surface to unite in- 

 timately with that of gelatine during the manufacture of the 

 paper, and the readiness with which this, under coating of 

 albumen, can afterwards be coagulated, by simply floating 

 it upon hot water, thereby rendering it no longer soluble in 

 water, enables a sufficiently glutinous surface to be retained 

 under the inky-print when finished, to establish the im- 

 portant property which the "transfer" must possess of 

 adhering to the stone during the operation of transferring/ 



