182 DRAWING BY THE AID OF PHOTOGRAPHY [Cn. VI 



to bring out clearly the features desired; then use a long focus photo- 

 graphic objective and get a small, sharp picture. The negative 

 should be about the size of a lantern slide, and it should be a good 

 printing negative. Make a large print on thick developing paper 

 exactly as described in the previous section ( 289). This print 

 should not be dark, but two or three shades lighter than the usual 

 print to give opportunity for the added shading. The picture should 

 be erect. 



When the print is dry, put it on a drawing board and with a carbon 

 drawing crayon, pen, India ink, and an air brush, if it is available, 

 the picture can be made almost perfect with a minimum of labor. 



In case the negative shows parts not needed or if the background 

 is not as desired, the superfluous parts can be eliminated and the 

 background made perfectly white by painting on the glass surface 

 of the negative Gihon's or other opaquing medium. In the print 

 there will be pure white where the opaque is painted on the glass. 

 Use a fine brush and put on a layer which does not allow any light 

 to pass. The opaque is put on the glass surface so that it can be 

 easily removed if desired. In case some parts are not light enough 

 or white points are to be added, use some of the white recommended 

 by the photo-engravers (Blanc d'Argent etc.) . 



As in all drawing, the actual object should be before the artist 

 when retouching the photograph, so that accuracy may be secured. 



291. Tracing pictures natural size on drawing paper. It 

 frequently happens in preparing the drawings for a book or for a 

 scientific paper that figures from another book or from a scientific 

 paper are needed. If there is to be no modification in the figure the 

 simplest method is to borrow an electrotype. If this cannot be 

 done and the picture is not available to put in the hands of the photo- 

 engraver for a new cut, or if one wants to make minor changes, it is 

 very easy to get a tracing on any good drawing paper as follows: 

 Put the picture on the glass of the drawing shelf (fig. IOQ) and place 

 over it some good drawing paper like Whatman's hot-pressed drawing 

 paper or Reynolds bristol board. Turn on the light, and even through 

 the thick drawing paper the outlines of the picture are so clear that 

 the tracing can be made with ease. After the outlines have been 



