PHOTOGRAPHING FISH 97 



which most easily affect the isochromatic film. 

 Therefore in fish photography they will be found 

 not only as quick as the ordinary extra-rapid plate, 

 but, owing to their sensitiveness to the colours just 

 mentioned, will yield a more perfectly exposed nega- 

 tive. Their value will be most noticeable when the 

 fish to be photographed is strongly coloured, where 

 bright yellow, red, and dark green may be side by 

 side. The ordinary plate would show only a slight 

 difference of tone between the yellow and red, and 

 perhaps none at all between the red and green, while 

 the instantaneous isochromatic would show a decided 

 difference in the three colours. Not giving the red 

 its full value, of course, because that can only be 

 obtained by using the slow isochromatic or by the 

 addition of a ray-filter. It is a rare thing, however, 

 to find a fish that will remain quiet enough to allow 

 of these being used. 



PART II 



ACCESSORIES AND THEIR PREPARATION 



To any one who has not attempted fish photography 

 it would seem an absolutely easy matter to beautify 

 the aquarium by adding vegetation and stones as a 

 background for the fish. That is exactly what I 

 thought when I first began aquatic photography, but 

 it did not take me very long to discover how mis- 



