﻿339 



1903. For an example of zinc etching, made without reduction, see 

 Box. Gaz. 61: pi. 22. 1916. The contrast between a zinc etching at a 

 one-half reduction and one reproduced without reduction may be seen 

 by comparing figs. 14 and 13 of the plate just mentioned. The originals 

 for the two figures were drawn in the same style, but fig. 14 was reduced 

 one-half and fig. 13 was reproduced without reduction. Such a pro- 

 cedure involved needless expense, since a negative had to be made from 

 fig. 14, reducing it one-half; then a print from this negative had to be 

 pasted in its place among the original drawings. Contributors often 

 send in graphs on co-ordinate paper, ruled in various shades of red, 

 yellow, or blue. The engraver can "screen" out the colored lines so 

 that they do not appear at all, but he cannot reproduce them satis- 

 factorily. Reproduction of such graphs by the half-tone method is 

 very unsatisfactory. If white paper ruled in black is unobtainable, get 

 a ruling pen and do your own ruling. The graph referred to above was 

 made in this way. 



Photolithograph. — This mode of reproduction is good for fine lines and 

 fine dots. The paper must be smooth and perfectly white, and the ink 

 must be dead black. The soft effect of a lithograph can be secured by 

 the printer, who can use an ink of lithograph color. Pencil drawings or 

 washes cannot be reproduced by this method. This is strictly a photo- 

 graphic method/ and is popular with investigators who can draw, since 

 it cannot be modified like a lithograph. See Bot. Gaz. 42 : pis. 19-28. 



Lithograph— -This method is expensive and somewhat uncertain, 

 since it involves redrawing by the lithographer. A crude drawing will 

 be improved by this method, but if the investigator can draw better than 

 the lithographer, the reproduction will suffer. No really satisfactory 

 lithographs have been made in this country, and there is great delay, 

 sometimes more than a year, in getting them from abroad. 



Heliotype. — This method is good for photomicrographs and general 

 work in black and white, but is rather expensive. In the preparation of 

 copy, different colors should not be used, but various shades of black may 

 be obtained by diluting the ink, so that there may be a range from dead 

 black to pencil color. The ink may be used as a wash. It is better not 

 to combine ink and pencil work in a drawing, for while the copy looks 

 well, the ink and pencil do not behave exactly alike when photographed. 

 If photographs or photomicrographs are to be reproduced, use a glossy 

 paper; even then, a skilful squegee will improve the copy. Since the 

 reproduction will lose a little in contrast, use a contrastypaper and 



