134 LITHOGRAPHY 



.the paper off the stono, we place it on a white slab of stone, and pour hot water over 

 it, it will resume its primitive state. 



The coat of gamboge ought to be laid on the same day it is dissolved, as by keeping 

 it becomes of an oily nature ; in this state it does not obstruct the transfer, but it 

 gives a gloss to the paper which renders the drawing or tracing more difficult, espe- 

 cially to persons little accustomed to lithography. 



The starch paste can be employed only when cold, the day after it is made, and 

 after having the skin removed from its surface. 



A leaf of such lithographic paper may be made in two minutes. 



In transferring a writing, an ink drawing, or a lithographic crayon, even the im- 

 pression of a copper-plate, to the stone, it is necessary, (1) that the impressions be 

 made upon a thin and slender body, like common paper ; (2) that they may be de- 

 tached and fixed totally on the stone by means of pressure ; but as the ink of a draw- 

 ing sinks to a certain depth in paper, and adheres rather strongly, it would be 

 difficult to detach all its parts, were there not previously put between the paper and 

 the traces a body capable of being separated from the paper, and of losing its ad- 

 hesion to it by means of the water with which it is damped. In order to produce this 

 effect, the paper gets a certain preparation, which consists in coating it over with a 

 kind of paste ready to receive every delineation without suffering it to penetrate into 

 the paper. There are different modes of communicating this property to paper. 



Besides the above, the following may be tried. Take an unsized paper, rather 

 strong, and cover it with a varnish composed of Starch, 120 parts ; gum arabic, 

 40 parts ; alum, 20 parts. 



A paste of moderate consistence must be made with the starch and some water, 

 with the aid of heat, into which the gum and alum are to be thrown, each previously 

 dissolved in separate vessels. When the whole is well mixed, it is to be applied, still 

 hot, on the leaves of paper, with a flat smooth brush. A tint of yellow colour may 

 bo given to the varnish with a decoction of the berries of Avignon, commonly called 

 French berries by our dyers. The paper is to be dried, and smoothed by passing 

 under the scraper of the lithographic press. 



Steel pens are employed for writing -and drawing with ink on the lithographic 

 stones ; in many establishments a sable brush is more frequently used. 



Engraving on stone, for maps, geometrical drawings of every kind, patent inven- 

 tions, machinery, &c., is performed with a diamond point as clearly and distinctly as 

 if executed on copper or steel plates ; to print these engraved stones, the ink should 

 be laid on with a dabber, not a roller. Another method is by preparing the surface 

 of the stone with a thin covering, or etching ground, of gum and black, upon which 

 the design is traced or engraved with an etching point ; it then appears in ivhite lines 

 upon a black surface. In this state the stone is taken to the printer, who applies ink 

 to the engraved part, and washing off the gum, the drawing appears in black lines 

 upon the white surface of the stone, and after being submitted to the process of 

 fixing, described below, is ready for printing. 



LitJiotint, a process of drawing upon stone was adopted, first, by Mr. J. D. Harding, 

 a few years back, and since by one or two other artists ; several works were at 

 the time executed by this method, which consists in painting the subject with a 

 camel's-hair pencil, dipped in a preparation of liquid lithographic chalk, using the 

 latter as if it were an ordinary colour, or Indian ink, sepia, &c. The results of this 

 process were, however, so uncertain in printing, that it has been almost, if not en- 

 tirely, abandoned. 



The process of printing a subject executed in lithography is as follows : Tho 

 drawing is first executed by the artist on the stone in as perfect and finished a 

 manner as if done on paper or cardboard : the stone is then washed over with nitric 

 acid, diluted with gum, which neutralises the alkali, or soap, contained in the chalk, 

 fixes the drawing, and cleanses the stone at the same time : this is technically called 

 etching. The acid is then washed off with cold water, and any particles of tho 

 crayon or other substances which may have adhered to the surface are removed by 

 tho application of a sponge dipped in spirits of turpentine : tho stone is now ready 

 for printing : it is slightly wetted, charged with printing-ink by means of a roller, 

 the sheet of paper, which is to receive tho impression, is laid on it in a damp state, 

 and the whole is passed through tho press. 



Chromolithography, or printing in colours from stones (xp&nu, colour), is a com- 

 paratively recent introduction ; but has been brought to such perfection, that works 

 of art of the highest pictorial excellence are sometimes so closely imitated, as to 

 deceive very competent judges. A portrait of Shakspearo, for example, executed 

 in chromolithography by Mr. Vincent Brooks, of London, from an' old oil painting, 

 is so marvellous a copy of tho original as almost to defy detection. Chromolitho- 

 graphy, as a beautiful medium of illustration, is now in very general use : the process 



