.' ~ Lantern Slides. • 37 



])al objection to the plates is that the glass varies much in thick- 

 ness, and is often marred by blebs and scratches, faults due solely 

 to carelessness in its selection. 



The glass of the Carbatt plates is aUout perfect, being thin, 

 clear and uniform. The emulsion requires only about one-half as 

 !ong an exposure as Anthony's, and when the exposure is just 

 right developes beautifully, but in cases of over-ex])osure it is not 

 so easily controlled. The best results are always obtained by 

 using the maker's formula for developer, and as this one is some- 

 what complicated it is not quite so readily prepared, particularly 

 if, as sometimes happens, only one or two slides are wanted. 



An excellent plan when a number of lantern slides are to be 

 made is for two men to work together, one to remain in the 

 dark room to develope plates, and the other to make the exposures. 

 By comparing results the proper exposure for the different nega- 

 tives is readily determined, and in consequence fewer plates are 

 spoiled. The worker outside readily notices changes in the inten- 

 sity of the light which would escape the attention of one who 

 spent much time in the dark room. 



Two men can in this way accomplish far more than if they 

 work independently, and are certain to learn more rapidly, for 

 each will notice some matter of importance that would have es- 

 caped the attention of the other. I have found that for this 

 method of working it is well to develope in large trays, about 7x9, 

 and to have at least two developers, strong and weak. Four or 

 more positives may be developed at once, and the work proceeds 

 as rapidly as the exposurers can be made. 



Exposures for lantern jjictures must be full, in order that de- 

 tail may be developed in the high lights before the shadows be- 

 come too dense. 



Nothing can be done to save an under-exposed positive, but 

 it must be remembered that only those are under-timed which 

 refuse to develop uniformly when placed in the normal de- 

 veloper. 



Generally the most satisfoctory results are attained by trying 

 to expose so that the positive will develop in a solution contain- 

 ing about one-half the normal quantity of iron, and which has also 

 a small quantity of the restraining bromide. If this plan is adopted 

 a plate which refuses to develop properly in the weaker solution 

 is pretty certain to come out when put into the stronger. If plates 



