BOTANICAL PHOTOGRAPHY 161 



Dealers in photographic supplies sell a box for making paper prints. 

 It is equally good for making lantern slides, but rather expensive. A 

 box which will give just as good results can be made in a few hours 

 (Fig. 29). 



Find or make a box about 18 inches high and large enough to have 

 a glass top 9X11 inches fitted into it. Fit a ground glass into it, about 

 8 inches from the clear glass in the top. On the bottom, put a red bulb 

 in the middle, with four white bulbs (50 or 60 watt) around it. The 

 red light can be plugged in separately and the four white bulbs can be 

 wired so as to glow only when the switch is closed ; or the lights can be 

 wired so that, with only one plug, the red light will be on as long as the 

 plug is in, but the white lights will come on only when the switch is 

 closed (Fig. 29). 



For holding the lantern-slide plate firmly against the negative — the 

 dull emulsion side of the lantern-slide plate and the negative should 

 always be in contact with each other — the device shown in Figure 30 

 is better than a hinged lid. 



With this box, the exposure can be estimated very accurately, since 

 the distance between the negative and the light is constant. With only 

 a ground glass to diffuse the hght, the exposure is likely to be too 

 short. Put one or two sheets of white paper on top of the ground glass. 

 With both ground glass and paper to diffuse the light, the exposure 

 should be about 2 seconds for a good negative. The number of sheets 

 of white paper should be increased or diminished until 2 seconds gives 

 an exposure which will develop fully in If minutes. With a dense 

 negative, the time will be longer; with a thin negative, it is better to 

 add one or more sheets of paper, so that 2 seconds will be about right 

 for the exposure. 



After the plate, film, or paper has been developed and rinsed for 

 about 10 seconds in the acid stop, place it in "hypo." 



The hypo removes the silver which was not acted upon by the ex- 

 posure to light. 



Lantern slides by reducing and enlarging. — If a slide is to be 

 made from a 4X5 or larger negative, there must be a reduction. A 

 camera is necessary. A 3jX4| camera is large enough. If any larger 

 size is used, the plateholder must be "kitted" down to 3jX4, the 

 standard size of lantern slides in America. In using the larger cameras, 

 mark upon the ground glass the exact size and location of the lantern- 

 slide plate. Fasten the negative in some convenient place where the 



