February, '17] WALDEN: insect photography 29 



especially when engaged in medical entomology or* similar lines, fre- 

 quently wishes to photograph interiors where the light conditions are 

 poor. The method used in making the illustration shown in figure 1 

 is useful when photographing directly against the light. The exposure 

 given was sufficient to fully time the darkest portion of the object and 

 was about ten times the normal exposure for the light conditions of 

 the room. Development was started in a developer containing four 

 or five drops of the carbonate solution instead of an ounce as ordinarily 

 used. After the detail appeared a few drops of the carbonate solution 

 were occasionally added, and the negative developed for about twenty 

 minutes. 



The prints intended for halftone illustrations are made on developing 

 paper. In fact, at the present time practically all of the prints sub- 

 mitted to the local engraver for halftone work are on this class of paper. 

 The loss of detail in our published illustrations has been due usually 

 to unsuitable paper or to careless printing from the halftone plates 

 rather than to poor halftones. 



Lantern Slides. — In making lantern slides, a hydroquinone devel- 

 oper similar to the one recommended by the late Professor Slingerland 

 has proven most useful. Also his potassium ferricyanide solution is 

 excellent for local reduction. Weak or slightly underexposed slides 

 can be considerably improved by redevelopment, the same as is used 

 to produce sepia tones on bromide paper, providing, of course, the 

 tone is suitable for the subject. It is often desirable to combine the 

 views from two negatives on one slide. This can be done by alter- 

 nately exposing each side of the plate, first covering one half of the 

 plate with a card, making one exposure, and then covering the exposed 

 side while the second exposure is being made. Care must be taken to 

 have the exposures similar. An easier way to accomplish this is to 

 make the first exposure on one plate and the second exposure on another 

 plate, using the latter for the cover glass. If the reversed image of the 

 second exposure is objectionable, the negative can be reversed in the 

 camera before making the exposure. 



A brief description of the method of indexing our negatives and prints 



^ Explanation of Plate 1 



Fig. 1. Laboratory stand and view camera. 



Fig. 2. Home-made bracket and tripod stay for photographing vertically. 



Fig. 3. Home-made box camera for photographing natural size. 



Fig. 4. The same with extension for photographing twice natural size. 



Fig. 5. "Parallex" enlarger with side removed. 



Fig. 6. Enlarger as used for printing. 



