SYXOPSIS OF THE EXHIBITION. 



Pabt I. — Processes of Engraving and Printing, Exclusive 

 OP THE Modern Photo-Mechanical Processes. 



[Alcoves 1, 2, 3. — Cases I-O and screens 1-4.] . 



The following- twenty-four nietliods or processes are represented ia 

 this division: (1) Engraving in relief (wood-engraving); (2) intaglio 

 eugraviug (burin work, line engraving); (3) etching; (4) mezzotint; 

 (5) dry-point; (G) aquati'it ; (7) imitation of crayon-drawing; (8) stip- 

 ple; (9) lithography; (10) soft-ground etching; (11) the sand manner; 

 (12) etching on glass (so called); (13) machine engraving; (14) galvau- 

 ography; (15) hyalography; (16) stylography; (17) chemitypy ; (18) 

 kerography ; (19) the wax process ; (20) the graphotype ; (21) clay sur- 

 face processes; (22) miueralography; (23) miueralotypy ; (24) nature- 

 printing. 



Although this list does not exhaust all the processes in use for the 

 production of printable blocks or plates into which photography does 

 not enter, it is yet believed to embrace most of those of any importance. 

 In the case of the leading processes the exhibition endeavors to convey 

 some idea of their history. Short technical explanations are given 

 under each heading. 



1. RELIEF ENGRAVING. 



Belief engraving is generally called wood-engraving, from the mate- 

 rial upon which the work is executed, although metal was occasionally 

 used in old times and is still used for certain purposes. In this process 

 the dots, lines, and larger surfaces composing the picture are left stand- 

 ing, while the spaces between and around them which are to appear 

 white are cleared away. If a block thus engraved is rolled up in print- 

 er's ink the lines, etc., accept it, while the spaces between them are left 

 untouched. A piece of paper pressed against the inked block takes up 

 the ink from the lines, etc., and the result is an impression. 



The invention of wood-engraving is lost in obscurity. It was first 

 largely used in Europe in the fifteenth century, and reached one of its 



705 

 Proc. X. M. 87 45 



