CH. VIII] 



PREPARATION OF LANTERN SLIDES 



209 



326. Printing the lantern slide from the negative. If the 



picture on the negative is of the proper size for a lantern slide, it is 

 put into a printing frame exactly as for printing with paper. Then 

 in the dark room a lantern-slide plate is put with its sensitive side 

 next the negative and arranged so that the picture will be straight 

 on.the lantern slide. The cover of the printing frame is put on and 

 held in place by the hands or by the springs. The exposure may 

 be in diffused daylight, or about 30 cm. from any good artificial 

 light (incandescent bulb, Welsbach gas light, kerosene lamp). 



Base 



FIG. i I 6. 



CAMERA FOR MAKING LANTERN SLIDES BY MEANS OF AN 

 OBJECTIVE. 



Base The base of the camera resting on the table. 



Objective The photographic objective in the middle segment of the camera. 

 The objective is shown as if the enclosing bellows were transparent. 



Front The front of the camera where the negative is placed. 



Reflector A white sheet of paper or cardboard placed on a shelf at 45. 

 This reflector serves to illuminate the negative. 



By varying the relative distances of ground glass, objective and negative, 

 the lantern slide can be larger or smaller or of the same size as the corresponding 

 part of the negative. 



The exposure required varies with the negative, but it is less than 

 for most developing papers. 



327. Developing the lantern slide. Any good developer may 

 be used, but as a rule the directions given in the box of plates are 

 the best to use with that brand of plate. One should develop until 

 the picture appears clearly. The temptation is to develop too 

 much and thus make the slide too opaque. Black, like printed 

 letters, should be opaque in the correct lantern slide, but there 

 should be all gradations from that to clear glass in the whites. 



