LITHOGRAPHY. 



Fresh impressions of lithographs, of steel, copper, 

 uid wood engravings, and of letter-press, may be 

 transferred to, and printed from the stone. The 

 paper used for this purpose is prepared with a 

 special composition ; and the ink is a mixture of 

 the writing and printing inks. Transfer impres- 

 sions from wood-engravings and letter-press may 

 be taken on the writing transfer-paper with the 

 best kind of type-printing ink. The transferring 

 process is the same as that already described. 

 This forms an important branch of lithography, as 

 impressions of copper and steel engravings may 

 be multiplied indefinitely without injury to the 

 original plates. Many subjects, such as music- 

 titles, &c. are engraved cheaply on a soft metal, 

 such as zinc, expressly to be transferred to the 

 stone. When the design is small, and wanted in 

 large numbers, it may be transferred many times 

 on one stone, and so many of them printed at one 

 impression. 



The grained paper process is a most important 

 invention of recent date. The method of prepar- 

 ing the paper is as follows : A sheet of copper or 

 other metal is grained on the surface by aquatint, 

 stipple, or ruling-machine ; paper, coated with a 

 white transferring ground, is passed through a ; 

 press on the face of the prepared plate, becomes 

 impressed with the grain, and can be drawn on ' 

 with chalks in the same way as a grained stone, j 

 The drawing is transferred to a flat or polished : 

 stone, in the same manner as writing. The great j 

 importance of this process will be better explained j 

 when we come to describe the steam lithographic 

 machine. 



Engraving on Stone is not engraving, properly 

 so called, but an adaptation of the process of 

 etching, whereby very delicate drawings may be 

 executed on stone. A hard, polished stone is 

 covered with a thin coating of gum, having a little 

 colouring-matter mixed with it, to allow the artist 

 to see his progress. On this ground the drawing 

 is executed with etching points of diamond and 

 steel of various breadths, so that broad lines may 

 be cleanly cut out. It is necessary that the sur- 

 iace of the stone should be cut into sufficiently 

 to remove the gum entirely, in making the line. 

 When the drawing is finished, any greasy matter, 

 oil, or tallow is rubbed into the lines, and allowed 

 to remain for an hour or so ; this is imbibed by 

 the stone where it has been exposed by the etching 

 point ; the other parts are protected by the gum. 

 The gum is then washed off, the stone damped, 

 and inked by the roller, and printed without 

 any further manipulation. It is obvious that, 

 as a much finer line can be scratched with a 

 diamond point than drawn with a pen or brush, 

 this process is capable of very delicate work. 

 It is extensively used in Germany in the produc- 

 tion of maps and other work. In printing en- 

 gravings on stone, the ordinary inking-roller 

 has sometimes to be supplemented by a dab- 

 ber made of rolls of flannel, charged with thin 

 ink ; this is dabbed over the surface of the work ; 

 any superfluity arising from the thinness of the 

 ink is readily removed by passing over a roller 

 with stiffer ink. 



Chromo-lithograpky is the most beautiful of all 

 the methods of printing from stone, and its proper 

 execution requires a very high degree of skill. 

 '1 he object being to produce, as nearly as possible, 

 imitations, of pictures in colour, it is necessary 



to employ a number of stones, each printing a 

 separate tint, to -produce the infinite variety of 

 colour in a finished colour-drawing. The usual 

 method of procedure is as follows : A careful 

 outline of the entire design is drawn on, or trans- 

 ferred to, a stone ; from this as many copies are 

 printed with transfer-ink as there arc colour- 

 stones, to which they are transferred as guides for 

 drawing in the different colours. On one of these 

 the general effect of the picture is sometimes 

 drawn in, and this, printed in a neutral gray, 

 forms the basis of the finished print. The other 

 stones are charged separately with the colours 

 necessary for the different parts, one having the 

 blue, with its modifications, another red, another 

 yellow, others with grays and secondary tints to 

 break and harmonise the others. It will be easily 

 understood that, in the arranging of the different 

 colours on the stones, the proper amount of force 

 to be given to each, and the effect likely to be pro- 

 duced by printing one tint over another, have all 

 to be considered, and give scope for a great deal 

 of artistic skill. There are many different methods 

 of making the tints on the stone ; the following is 

 a usual one : all parts of the stone not intended 

 to print are covered with a strong solution of 

 gum and acid, which is allowed to dry ; those 

 parts that are to have a full tint are scratched 

 round with a point, the stone is slightly warmed, 

 and a tinting-ink of greasy composition is rubbed 

 over the surface with a piece of woollen cloth till 

 a flat grayish tint is produced. This forms the 

 middle tint, and is modulated towards the high 

 lights, which have been covered with gum, with a 

 scraper ; and those parts intended for a solid tint, 

 which are shewn by the scratched line appearing 

 sharply through the tinting-ink, are filled in with 

 lithographic ink. The stone is then strongly 

 etched, and is ready for printing in the usual 

 manner, except that coloured inks are used instead 

 of black. When it is considered that as many as 

 twenty or thirty different stones are sometimes 

 used in printing one picture, and that they are 

 printed one after the other on the same paper, it 

 will be understood that a great amount of care is 

 necessary, in printing, to see that each impression 

 is exactly fitted to the others, or txzctiYrtgisttred, 

 as it is called. If any one of the impressions 

 were misplaced, even a very little, the result 

 would be a failure. Several appliances are used 

 to secure this uniformity, into the details of which 

 we need not enter. 



Ordinary chalk-drawing coloured with out or 

 two tints, is a simple modification of this process, 

 and is performed in the same manner. 



We have now roughly sketched the principal 

 kinds of lithography, but it is to be understood 

 that they are all capable of various modes of 

 treatment Those we have described have been 

 chosen with the idea of giving the best possible 

 explanation of the theory of this beautiful art. 



Lithographic prtsses vary in constriction, but 

 the chief points in their mechanism are these : 

 The scraper (s, fig. 9), which applies the neces 

 sary pressure, is a wedge-formed plate of brass or 

 boxwood, fixed to the bottom of the scraper- 

 holder, with its edge downwards. The table on 

 which the stone is placed, and on which the 

 tympan (/), an iron frame covered with leather, 

 which covers the paper on the stone while being 

 printed, is brought down, is, by means of a 



