Ch. VI] DRAWING BY THE AID OF PHOTOGRAPHY 



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traced, the finishing can be done on a drawing board, having the 

 original picture for reference. 



§ 292. Drawings by a projection or a photographic objective. — 

 For light use an arc lamp or a stereopticon mazda lamp ; use a nega- 

 tive which is not too dense or a lantern slide. It is placed in the 

 lantern-slide holder and by means of an ordinary projection objec- 

 tive, or better by a photographic objective, the image is projected 

 upon the drawing paper (fig. no). For the proper size either the 



Condenser 



Fig. 1 10. Magic Lantern with Projected Image. 

 (From Optic Projection). 



A small arc lamp connected with the house lighting system is used for light in 

 this case. 



W, So, S — p Electric wires, lamp socket with key switch (s) and a separable 

 attachment plug. 



R Rheostat. 



Condenser, W A three lens condenser with a water cell to absorb radiant heat. 



LS Lantern slide. 



Axis, Objective The principal optic axis of the condenser and of the objective 

 in one line. The cone of light crosses within the objective at (c). 



Screen Image The real image projected upon the screen. 



projection apparatus or the drawing surface must be movable. For 

 most artists it is better to make the drawing two or three times the 

 size which it is to have after engraving. The reduction minimizes 

 the little irregularities which are almost sure to be present. 



When the size is correct, and the image sharply focused, one can 

 trace directly on the drawing paper with a pencil all the lines and 

 details which it is desired to represent. Then the drawing can be 

 inked in at leisure, remembering always to have the object for con- 

 stant reference and thus insure accuracy. 



In making the negatives for projection it is very desirable that 



