NEGATIVE MAKING 



93 



resorted to, the radiant must be placed upon 

 the table in front of camera and behind the 

 object, at such a height that its center shall 

 coincide with that of the lens. The rays may 

 be condensed upon the object by means of a 

 bull's-eye condenser or diffused by placing a 

 sheet of ground glass between the light source 

 and object. The proper length of exposures 

 must be learned by practice, but they will be 

 somewhat longer than those required for dif- 

 fused daylight illumination. 



Should our camera be one of the usual 

 short bellows form it will be of little or no 

 use in making enlargements or photo-macro- 

 graphs without certain modifications. To 

 start with, an upright board should be at- 

 tached to the front end of sliding platform, 

 with a circular opening at precisely the same 

 height as that in camera front. The lens 

 flange of latter or better a duplicate one 

 must be fastened to this board to carry the 

 lens instead of camera. If the front of camera 

 is removable, so as to admit all of the rays 

 projected by the lens, the manipulation will be 

 very simple, for we have the same conditions 

 as in the last example: a lens and focusing 

 screen moving independently. The object 

 may be centered and brought to desired 



