1887.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 725 



transfers to or printable pictures produced directly upon stoue or zinc 

 for the lithographic press ; and (3) intaglio plates, which are printed on 

 the roller press, like other engraved or etched plates. The second class 

 consists of two divisions, the common characteristic of which is that, in 

 the nature of the plate as well as in the printing, the processes involved 

 differ from all previously known. The first division comprises the col- 

 lographic processes ; in the second, the Woodbury type stands alone 

 by itself. For a word concerning these, see below, paragra])hs 3 and 4. 



The second classitication, according to the originals used, clearly 

 shows the capacities of these processes, and tbeir tendency to get rid 

 not only of the engraver (except as an assistant in retouching or curing 

 defects), but even of the designer. Its first division consists of the re- 

 production of line work or work in dots (pen-and-ink, pencil, and crayon 

 drawings, etc.) ; the second of printable blocks made from washed draw- 

 ings and oil paintings, and finally directly from nature and life. It is 

 evident that this is the crowning achievement of the photo mechanical 

 processes, for at first sight it would seem quite impossible to translate 

 the flat tints of a washed drawing, or the infinity of imperceptibly gradu- 

 ated tints in a finished painting and in nature, into textures capable of 

 producing similar eftects in the printing press. That this apparently 

 insolvable pioblem has been solved, with a very fair measure of success, 

 is clearly made evident by the proofs here shown. 



Special attention is invited to the specimens of early work given to 

 the National Museum by Mr. J. W. Osborne, which lends to the exhi- 

 bition something of an historical character. 



1. RELIEF PROCESSES. 



These processes furnish blocks which can be printed in the type 

 press, like wood-engravings. They are either etching processes, or in- 

 volve casting or electrotyping from hardened gelatine films. Their 

 products are known as phototypes, photo-electrotypes, phototypo- 

 graphic etchings, typogravures, etc. 



Frame im.— Early icorlc by Paul Pretsch, about 1854-1857.— Nos. 669, 

 671, 672, 675 from prints; No. 673 from a sepia drawing; Nos. 670 and 

 674 from nature. 



Frame IW.— From penand ink sketches.— All the originals from which 

 these reproductions were made were drawn in the usual manner em- 

 ployed by artists, upon ordinary drawing paper, most of them without 

 any thought of photo chemical processes. No. 676, by Ives & Barret, 



