172 NATURE-STUDY REVIEW [12:4— April, 1916 



work. Plates are cheaper than films of the same quality, and will 

 give better results in the hands of the average worker. 



For nature work, the writer has found the following plates very 

 satisfactory: Seeds Ortho L, Hammers Ortho. and Cramer's 

 Medium Isochromatic. Of the three, the latter has proven de- 

 cidedly more satisfactory than either of the other two. There are 

 other plates on the market probably of equal value with the 

 above. 



Preliminary Work 



The novice should acquire an acquaintance with his camera 

 and an introduction to developing by confining his first efforts to 

 landscapes, trees, buildings, etc. Here the help of someone who 

 has had previous experience in photography will be of great value. 

 Suppose a tree in the open is selected as the subject to be photo- 

 graphed, the procedure will be as follows: 



The plate holders should be loaded with the plates, in a light- 

 tight room which should be illuminated by a ruby light; if no 

 "dark room" is available, almost any room will serve after dark if 

 the shades be drawn. The plates should be placed in the holders 

 with the emulsion side (coated with gelatine and silver salts) out, 

 or the uncoated glass side in. The sides can be determined by 

 reflecting the ruby light from the two surfaces. The coated side 

 appears dull, the uncoated side shiny. 



The camera on the fully opened tripod must be placed so that its 

 back is to the sun, which may of course be either somewhat to the 

 right or left. The diaphragm should now be opened wide, the 

 .time pointer set at "T," and the shutter opened. The photo- 

 grapher adjusts a black cloth over his head and the ground glass of 

 the back, and moves the lens forward or backward until the object 

 seems in fairly sharp focus. The exact focus is then obtained by 

 use of the rachet screw that moves the travelling bed to which the 

 lens-holder is attached. (In purchasing a camera see that it is 

 provided with this.) It is probable that the image of the object 

 will be too large; if so the camera must be moved farther away 

 from the object, and refocused (the lens will need to be run back 

 toward the ground glass) ; if the image is too small, the camera 

 must be taken nearer the object, and refocused (the lens will need 

 to be run toward the object). Bear in mind that the nearer the 

 camera is to the object, the larger the image will be, and vice versa ; 



