THE A B C OF PHOTO MICROGRAPHY 



And yet I am constrained to enter a plea 

 in favor of dispensing with the ocular (cer. 

 tainly with the Huyghenian form) , in low and 

 medium power work. You will do more and 

 better without than with it. Look at the 

 section of Echinus spine (frontispiece of this 

 book), made with a cheap students' two-third- 

 inch objective of two systems without an eye- 

 piece, and note its almost perfect definition 

 and flatness of field, together with evenness 

 of lighting. Then photograph the same sub- 

 ject under the same amplification, using any 

 achromatic objective you may choose in con- 

 nection with a Huyghenian eyepiece, such as 

 accompanies the usual students' microscope. 

 Make a print of it and compare with the 

 reproduction. If it equals the latter I shall 

 have nothing more to say in favor of using 

 the objective alone. If for any reason you 

 should prefer to employ an ocular, then by 

 all means procure one of Spencer's Aplanats, 

 for use with achromatic object glasses, if you 

 desire the best results in your work. 



Blocking out Backgrounds. Although the 

 details of a negative must not be retouched or 

 changed in any manner, it is quite legitimate 

 to block out the background of an object re- 

 quiring to be shown as a whole, by painting 



