MAKING SLIDES BY REDUCTION.
The method of making lantern slides by reduction presents more difficulties than the process just described, but is tolerably easy to one who has done a little copying. In principle, it is exactly similar to any other form of making reduced copies, the only difference being that one has to work from a transparent original. The apparatus used for making daylight or artificial light enlargements may be used for this purpose, provided, of course, that the various parts permit of the desired extension. The rails shown in Fig. 456 will also he needed. Those who have this fitted up will want nothing further, but for general amateur work the arrangement shown in Fig. 456 will be found to answer well. It con sists of a board, which may be fixed making slides by reduction by artificial light as a rule ; but, if daylight is used, most of the processes except carbon can be employed.
Gelatino-Bromide.--This has been fully
dealt with in the chapter on Development Processes of Printing. The emulsion is practically the same as used for bromide paper. The same remarks apply to the other processes ; the only point worth ' urging is the strict necessity for freedom from spots, markings, etc. For artistic effects, and when the extra amount of work is not of consequence, the carbon , process will be found a most admirable one. Its long range of contrast, beautiful gradation, and the fineness of the grain of the deposit fit it especially for the pro duction of the highest class slides. The slides are made by contact in the same' way as a carbon transparency. Where the negative is larger than the slide, a re duced negative must first be made. The Albumen process is considered by many to be the finest process available for this work. For particulars, see the section on that subject.