1864.] 483 [Osborne. 



Mr. Osborne, present by invitation, exhibited a port-folio 

 of lithographic plates, and explained his process of copying 

 by Photo-lithography. Mr. Osborne said : 



This method of combining photography with lithography is not 

 new ; it is a tried and tested process, which for upwards of five years, 

 has been actively employed by the government of the British Colony 

 Victoria, for the production of maps. The invention dates from the 

 19th of August, 1859, and the first ofl&cial map was produced by it 

 on the 3d of September following; since which time several thousand 

 different original maps have been photo-lithographed by its means, and 

 sold to the public. The saving, both in time and money, which its 

 introduction has effected, is very great; and the government of the 

 colony has erected, according to my suggestion and plan, a substantial 

 ofl&ce consisting of several rooms, exclusively for the prosecution of 

 this method of reproduction. In 1861, the Victorian Parliament 

 acknowledged my services, and the estimation in which they held 

 the process, by voting me unanimously the sum of £1000. 



The general history of photo-lithography, and the details of the 

 various processes which have been put forward from time to time, is a 

 subject too extended for me to discuss on the present occasion ; 1 shall 

 confine myself therefore, to a description of my own solution of the 

 difficuhy, the superiority of which, for certain kinds of work at least, 

 I believe now to be undisputed. 



Before proceeding to details it may be well to state, that the pro- 

 cess is designed and fitted for the reproduction of existing originals 

 only, such as maps and plans, engravings, pen-and-ink drawings, 

 MS. and printed documents, &c., and not for producing portraits or 

 views directly from nature. The problem to be solved may be de- 

 fined, more accurately, as follows : From a given original existing as 

 a black and white drawing or engraving, to produce by the chemical 

 agency of light, a fac-simile on stone, identical in character with an 

 ordinary lithographic drawing, which has been fitted for the printer. 



The first step in the process is the production of a negative, which 

 shall bear the desired relation to the original in size. This is done 

 by placing the latter upon an upright plan-board, and the camera 

 opposite to it, taking care that the plan-board and the ground-glass 

 slide of the instrument are perfectly parallel, and that the distance 

 between them is such as to give a copy of the desired dimensions. 

 The negative picture is then taken in the ordinary way on collodion, 

 but with numerous precautions, so as to secure the best possible result. 



