160 W. M. GRAHAM—THE PHOTOGRAPHY OF DIPTERA. 
PRINTING. 
Photographs of insects to be effective should be printed upon a glossy paper, 
as when printed upon a rough paper much of the detail is lost. The choice then 
is between P.O.P. and glossy gaslight paper. 
Gaslight paper, in my opinion, produces the more effective prints, but the 
makers of half-tone blocks seem greatly to prefer prints on P.O.P. for use in 
block-making. I have found glossy Gravura gaslight paper most suitable for 
these prints, as this paper permits the use of a dilute Farmer’s Reducer after 
development to improve contrast and to remove friction marks. 
1 have found Ilford P.O.P. (white) most suitable for use in the tropics, as it 
resists the injurious action of solutions above 80° F. better than other papers IJ 
have tried for this purpose. 
