BOTANICAL PHOTOGRAPHY 167 



water areas. After washing out the hypo, stain the shde in an aqueous 

 anilin bkie or light green for 10 or 15 minutes. When dry, use a brush 

 to color the land areas orange or any desired color. The second color is 

 likely to be more satisfactory if very dilute. 



With all slides which are to be colored, it is better to omit alum 

 from the hypo solution. 



For graphs, use the same method, except that hypo solutions with 

 alum and acid may be used. 



Lantern slides can be made from typewritten tables in the same 

 way. The paper should be pure white and the letters, dead black. 

 Illustrations in books can be copied in the same way. 



While nothing surpasses a process plate for negatives from which 

 you wish to get dead black and clear glass in the lantern slide, or dead 

 black and pure white in a paper print, process films are very good and 

 convenient for filing and are in no danger from breaking. 



ENLARGEMENTS 



Lantern-slide plates are often used in making photomicrographs of 

 histological preparations, but even when a 5X7 plate is used, an 8 X 10 

 enlargement, or even an 11X14, is better for reproduction, assuming, 

 of course, that the negative is good enough to stand enlargement. If 

 the negative is sharp and has no defects, a glossy paper can be used; 

 but if the negative lacks a little in sharpness or has defects, a paper 

 with a velvet surface is better, for the large print can then be touched 

 up with a pencil or pen and, when reduced to the size used in scientific 

 journals, the reproduction will be better than the engraver could have 

 obtained from a small print. Any prints as small as 3jX4j or even 

 5X7, should be on glossy paper and should be squeegeed, if they are 

 to be only 4 inches wide when reproduced. The engraver recommends 

 glossy paper for all prints. 



While the enlargement from photomicrographs is the kind which 

 comes within the range of histology, it is better to practice with nega- 

 tives of trees, flowers, and people. Select your best negatives and use 

 a paper with a velvet surface to begin with. 



The negative can be placed in your camera where you place a plate 

 for exposure. You can cut the partition out from the plate holder — 

 except a small border to hold the plate — and then put the negative in 

 as you would a plate; or you can make a frame, just the size of a plate 

 holder to hold the glass negative. For fihns, use two clear glass plates 



