M. TECHNOLOGY. 481 



4th, the unlimited number of impressions that may be made 

 on any kind of lithographic press, and the avoidance of all 

 necessity for the preservation of designs on stones, since a 

 transfer can be made from the original plate at any time in 

 a few minutes. 34 (7, V. 



THE GILLOTYPE. 



A process known as the Gillotype, invented by M. Gillot, 

 for producing printing-blocks by etching on zinc, has been 

 lately introduced very extensively into use in Paris, where it 

 is employed for the illustrations of newspapers and maga- 

 zines. A paper is first prepared by covering India paper 

 with one or two films of gelatin solution, applied very thin- 

 ly and evenly, and allowed to dry; after which a coating of 

 cold starch paste is put on, and subsequently a little gam- 

 boge dissolved in water. The picture is drawn in fatty ink 

 upon the paper, and laid with its face downward upon the 

 zinc, the surface of which must be well cleaned to remove all 

 grease, A sheet of paper moistened with hydrochloric acid 

 is placed upon it, and above this sheets of dry paper, and the 

 whole passed two or three times through a lithographic press. 

 The back of the paper containing the picture is then to be 

 well moistened with water, which allows it to be removed 

 from the zinc, leaving behind the fatty picture. The plate 

 is then washed with a soft sponge, and subsequently with 

 gum water, to which a little hydrochloric acid has been add- 

 ed, and the whole allowed to dry upon the metal. We now 

 have an ordinary zincograph plate, from which an impression 

 can be taken as from a lithographic stone ; but for relief 

 printing etching is required. A fatty or lithographic ink is 

 applied to the plate and allowed to dry; and over the whole 

 surface is then spread, by means of a tuft of cotton, some 

 finely powdered rosin, which attaches to the greasy particles, 

 and imparts to the ink a consistency sufficient to protect the 

 covered parts from the action of the sun. The other portion 

 betw^een the lines and letters is freed from the powder by 

 means of a second tuft of clean cotton, after which the bor- 

 ders and back of the plates are covered with shellac varnish. 

 The plate is then introduced into the etching solution in a 

 kind of trough, which is made to rock back and forward all 

 the time, with the object of Avashing off continually any salt 



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