LANTERN SLIDES. 
151 
quite clear. Next, there must be transparency in the 
shadows, i.e., in the image of the object; if the image- 
details are blocked up by over-density or fog, the slide 
cannot be good. Again, the whole must neither be too 
dense nor black and white, nor yet pale and “washed- 
out” in appearance ; we require pluck without hardness. 
Lastly, the colour of the image must be suitable ; and 
for our purpose this colour should be a good black, or as 
nearly approaching black as possible. Happily, this 
tone is the easiest of all to get with such slide-plates as 
we shall recommend; it is difficult to obtain warm tones 
without inducing fog. 
We do not propose to run the risk of confusing the 
reader by discussing more than two kinds of plates; and 
it happens that the same developing solution answers 
well for both. Moreover, as probably the worker has 
made his negatives on quarter-plates, or on lantern- 
slide-size plates, we need give but little attention to any 
process of printing except “ by contact.” 
Presuming that the negative is nearly the size re¬ 
quired for a lantern slide (a plate three-and-a-quarter 
inches square, with probably a two-and-threequarter 
or three-inch picture on it), the printing is performed as 
if the slide-plate were a piece of paper; the negative is 
laid face up in a printing-frame, the slide-plate face 
down on the negative : the frame closed, and the whole 
exposed to light as in the case of a print on bromide 
paper. But there is a slight advantage in copying the 
negative in the camera, as thereby a somewhat greater 
sharpness of definition can be obtained; the advantage, 
