CHAMBERS'S INFORMATION FOR THE PEOPLE. 



ink, with a little water and a gentle heat, may be 

 rubbed down in the same manner as china-ink. 

 The subject may be traced with tracing-paper, 

 and the drawing proceeded with in the same 

 manner as on paper ; the only difference being, 

 that it must be reversed on the stone. Great care 

 is necessary in handling the stone, as its affinity 

 for grease is so keen that a finger placed on it 

 would develop into a black blot in printing. When 

 the drawing is finished, it is covered over with a 

 solution of gum-arabic in water ; this gumming is 

 an indispensable part of the process, and acts in 

 several ways : it fills up the pores of the stone on 

 the undrawn parts, prevents the greasy lines of 

 the drawing from spreading, and resists the adhe- 

 sion of accidental grease stains in handling. The 

 stone is then removed to the printing-press (to be 

 afterwards described), and prepared for printing. 

 As this preparation is the same for all descriptions 

 of work, we will briefly describe it here. When 

 the stone is fixed in the press, the gum is washed 

 off with clean water. We may observe, in pass- 

 ing, that however carefully the gum may be washed 

 away, a little always remains in the pores of the 

 stone, assisting the water to resist the ink in the 

 subsequent printing. The stone is then damped 

 with a canvas cloth, and a roller (made of wood 

 or iron, covered with one or two thicknesses of 

 flannel, and an outer covering of fine leather) 

 charged with printing-ink, is passed several times 

 over the stone, till every part of the drawing is 

 thoroughly inked. In some cases this inking up 

 is performed with a piece of rag smeared with ink, 

 but the result is the same. If there have been 

 any accidental grease or finger marks on the stone, 

 they will appear with the inking. They must be 

 removed, if on the margin, by polishing with Water- 

 of-Ayr stone, or with acid, or if close to the work, 

 scraped out with a sharp knife. When the drawing 

 is thus rendered satisfactory, the stone is washed | 

 over with a weak solution of nitric acid in gum 

 water. This etching-, as it is called, is another 

 indispensable condition, and also acts in several 

 ways. If applied too strong, it would remove the 

 drawing completely from the stone, but when 

 diluted to the proper degree, it gently eats away 

 the surface of the bare parts of the stone, opening i 

 up the pores for the better reception of the gum | 

 afterwards applied, thoroughly cleans it from 

 grease soils, and sharpens the lines of the drawing. 

 When the stone is sufficiently etched, the acid is 

 washed off with clean water, and another coating ' 

 of gum applied ; when this is dry, it is again washed 

 off with water, and usually, the whole drawing, or i 

 at least what appears on the surface of the stone, 

 is washed off with turpentine. From all that can 

 be seen on the stone by the uninitiated, the whole 

 work has been lost, but it is only the black which 

 is removed, the grease is in the stone, and that is 

 all that is necessary. This washing out is done 

 to get rid of the writing-ink, which differs in com- 

 position from the printing-ink, and is better 

 removed. The stone is now damped with a cloth, 

 and inked with the roller till the drawing is all black 

 again ; a piece of paper is placed on the top, 

 passed through the press, and when taken off has 

 received an impression from the drawing. The 

 damping and inking is repeated for every impres- 

 sion, and when the stone is put away or left for a 

 time, it is, for preservation, covered with the in- 

 dispensable gum, which, of course, must be washed 



off again when the printing is resumed. The ink 

 for black printing is composed of Paris black, 

 ground up with varnish made from boiled lin- 

 seed oil. 



Chalk-drawings are executed on a grained 

 stone, coarse or fine, according to the nature of 

 the work. As a chalk-drawing is capable of very 

 soft effects in shading, this process is much better 

 adapted for such subjects as portraits and finished 

 pictures than that last described. The litho- 

 graphic crayon works on the surface of the grained 

 stone exactly in the same manner as the ordinary 

 drawing-chalks on rough crayon-paper. The 

 method of drawing is similar, and needs no ex- 

 planation. When the drawing is finished, it has 

 to undergo precisely the same operation to fit it 

 for printing as the writing on stone. The printing 

 of a chalk drawing requires to be more carefully 

 conducted than a line-drawing, on account of the 

 grain on the stone ; the proper inking with the 

 roller particularly being a very delicate operation. 



Writings and drawings made on prepared paper, 

 and transferred to the stone for printing, form, per- 

 haps, the most important item in general litho- 

 graphic work. The paper is prepared on one side 

 with a coating of a mixture of isinglass, flake- 

 white, and gamboge, and afterwards smoothed by 

 being passed several times through a press over a 

 heated stone. The writing or drawing is made on 

 this preparation with a pen or fine brush, with 

 the lithographic writing-ink, in the same manner 

 as drawing on stone, with this difference, that it 

 does not require to be reversed, since the transfer- 

 ring does that for it. Transparent tracing-paper 

 can be prepared with the composition, and is used 

 where a fac-simile of any other subject is wanted. 

 The paper is put on the top of the drawing or 

 writing to be copied, and as the coating is not 

 thick enough to affect the transparency much, it 

 can be traced through with the pen like an 

 ordinary tracing. When the drawing is finished, 

 it is transferred to the stone in the following 

 manner. The paper is put for a few minutes 

 between damped blotting-paper. A warmed 

 polished stone is put in the press ; the paper is 

 then placed with the coated side upon it, and 

 passed several times through the press, after which 

 the paper is damped with water and gently rubbed 

 with the fingers till it comes easily off, leaving the 

 work adhering to the stone. The stone is gummed 

 over, and proceeded with as already described. 

 After the first inking-up, and before the etching, 

 any defects in the transferring can be touched up 

 with a pen or brush. 



Although liable to accidents in transferring, 

 this process, when carefully performed, is capable 

 of very fine work, and has almost entirely super- 

 seded drawing directly on stone, except perhaps 

 in cases where the value of the drawing is such 

 that it is not considered expedient to run the risk 

 of transferring. For circulars and commercial 

 work generally, it is invaluable. 



Autography is the name given to a variation of 

 this process, executed on common writing-paper, 

 without preparation, with the lithographic ink. It 

 is transferred in the same manner as that described, 

 except that it is damped with diluted nitric acid, 

 and only requires to be passed once through the 

 press. It is only used in the case of any one 

 wanting copies of circulars or other matter in their 

 own handwriting. 



