Lithographic Process. 235 



rent paper; blotting paper; and printing paper. Tlie transpa- 

 rent paper is for the tracing of drawings, in order to transfer them 

 to the stone ; which may be done either in the ordinary way, by 

 rubbing the back of the drawing with black-lead, and, having 

 laid it on the stone, marking the outlines with a tracing needle, 

 or by making the drawing on the paper with the softer chemical 

 ink already described, and, having laid it on the stone, passing 

 it through a press ; in which case the paper must undergo a par- 

 ticular preparation ; and is then called prepared transfer paper. 

 The blotting paper is used principally as a covering for the paper 

 which is to be printed. With regard to the printing paper, the 

 best is the half-sized, or wholly unsized paper used for copper- 

 plate printing. It ought to be moderately wetted, and then com- 

 pressed, and left for twenty-four hours before it is used. 



The description given by M. Senefeider of the various kinds of 

 lithographic presses is not susceptible of abridgement, and would 

 be unintelligible without the plates. He acknowledges that this 

 is a part of the art capable of great improvement; for that at 

 present too much is trusted to the skill and attention of the 

 printer. 



We proceed to the account of the different manners of litho- 

 graphy. They are divided into two principal branches — the ele- 

 vated, and the engraved manner. In the first, all thos,e parts of 

 the stone that are covered by a greasy ink, resist the action of 

 the acid poured over the whole surface of the stone, by means of 

 which the other parts of the surface become corroded ; they 

 stand therefore higher than the latter, as if elevated from the 

 plain surfirce of the stone. In the second manner, all those lines 

 or parts of the drawing or writing which are to give the impres- 

 sion are engraved into the surface of the stone by means of a 

 sharp needle, or bitten into it by the action of an acid. 



The sub-divisions of the elevated manner, are 1st, the pen, or 

 hairbrush drawing ; 2d, the chalk manner; 3d, the transfer man- 

 ner ; 4th, the wood-cut manner; 5th, the scraped manner; and 

 6th, the sprinkled manner. 



With reference to the pen or hairbrush drawing, the stone, in 

 order to prevent the chemical ink from spreading, ought to be 

 slightly prepared, by washing it with a strong solution of soap 

 and water, and subsecjiiently with pure water, which ought to be 

 carefully wiped off. The drawing is then to be made cu the 

 stone with the chemical ink already described. When dry, the 

 biting in with acid may commence. Tliis is effected eitlier hy a 

 flat varnishing Inrush, or by eilusion. In the first case, a com- 

 position of aquafortis, and three or four parts of water is repeat- 

 edly and uniformly passed over the surface of the stone; in the 

 second case, the stone liaving been previously phiced in the 



pitched 



