THE BOOK OF THE LANTERN. 137 



seem reluctant to give anything but a very poor trans- 

 parency. A really good negative will give a good print 

 on paper, glass, or indeed on any other possible material, 

 but at the same time a negative, which from its thinness 

 would require special management in ordinary printing on 

 albumenised paper, will yield a fine transparency on glass 

 with half the trouble. In other words, a negative taken 

 purposely for lantern work need not be so dense as one 

 destined for the ordinary printing-frame. The precautions 

 used in dealing with a thin negative in the one case, must 

 be observed in the other ; for instance, the careful printer, 

 in producing a paper print from such a negative, will take 

 his frame far from the window of his room, and give it a 

 very protracted exposure, and, by coaxing it in this way, a 

 good dense print is obtainable. Exactly the same treat- 

 ment is necessary in producing a lantern-slide from the 

 same picture. Instead of holding the printing-frame a foot 

 or two from the gas-burner, as already recommended, let it 

 be removed 6 feet away from the flame, and be given a 

 greatly-increased exposure by the rule already indicated. 



I have advised that the focussing-screen of the camera 

 should be marked with a 3-inch circle, to which the 

 picture should be limited. A still more effective plan, 

 however, is to cover the ground-glass with a card- 

 board mask, having a 3-inch hole in its centre, which 

 can be placed in situ when required. The operator can 

 then see at a glance whether his picture is nicely composed, 

 and will have a very good idea of its ultimate appearance 

 as a lantern-slide on the sheet. Most photographers carry 

 into the field with them more than one lens, and it is espe- 



