and Laboratory Methods. 1843 



come from the sky. I spoiled dozens if not hundreds of plates when I began 

 making lantern slides, because I did not so illuminate my negatives. I followed the 

 best books I could get ; they all said a ground glass should be used. If camera 

 and negative are horizontal, half the light comes from the earth and one-half the 

 field will be less brightly illuminated than the other, ground glass or no ground 

 glass. One day when there was snow on the ground, I made a fine lot of slides. 

 I invited my neighbor Kodakers to see them ; they wanted to see me " do it 

 again." Of course I agreed. The snow had melted, and every slide was a 

 failure. The next day I tilted my machinery as shown in the figure, until all 

 the light was skylight, and I have had no trouble since. The sun, of course, 

 must not shine on the negative. 



The lantern slide plates must be fresh. Do not buy them of dealers. Send 

 direct to the manufacturers. I learned this also by dear experience. I know 

 how to use just one kind of plates and one developer. They give perfectly satis- 

 factory results. I have no doubt that other plates and other developers would 

 do as well, but they could not do better. Accordingly, without disparaging any 

 brand of either plates or developers, I shall give exact details of how I make 

 slides and what I use. Any beginner or any one else who cannot make slides 

 that show in the high lights perfectly clear glass, can learn to do so if he will 

 heed the following directions accurately : get Seed's lantern slide plates from the 

 factory ; use for a developer equal parts of " A '" and " B " made up as follows : 



( Water - - - - - - - 16 oz. 



A ■< Hydrochinone ------ 120 grains 



( Sodium Sulphite crystals - - - 1 oz. 



( Water ------- 16 oz. 



B -<^ Caustic Soda ------ 60 grains 



( Potassium Bromide ----- 60 grains 



Arrange an apparatus like the one in the cut ; point it at ten o'clock on a 

 bright sunny day toward the southwestern sky. Five seconds exposure with a 

 128 stop and a medium dense negative would be the right time for my lens, an 

 anastigmat, series III A. It will serve for a beginning time perhaps for any 

 lens. If the time is not right it can be regulated; if the image begins to come 

 between forty and sixty seconds development, a good slide can be made by arrest- 

 ing the development at the proper time, that is, when it is slightly darker than 

 it should be, as it will wash out some in the fixative. If the image is clearly 

 seen before twenty seconds, the exposure was too long ; if only after ninety 

 seconds, it was too short. These directions should be unnecessary, however, as 

 no one should waste his time trying to make a lantern slide who cannot make a 

 good negative ; the cheapest way to learn how to make a good negative is to take 

 a few lessons of a good landscape photographer. 



If one has not to reduce his negative, a lantern slide can be made by contact 

 exactly as a velox print is made ; place the film of the lantern slide plate next to 

 the film of the negative, and expose it to a perfectly steady source of light like 

 an incandescent electric lamp or a Wellsbach burner ; a coal oil lamp or a candle 

 will do if the flame is always kept the same ; two seconds, a yard away from a 

 Wellsbach burner with a medium dense negative, will be a good time to try. 



