Thus far we have been dealing with slides made by contactóthe lantern plate in contact with a negative of the same size or smalleróbut this limits us to making slides from a negative or a portion of the negative in. square. But the negative or the image to be included may exceed this, and we must then adopt some method of reducing the subject to the size we require. This is done by copying, the negative being set up and photographed just as a view or portrait, the subject being made 3^ x 3^ in. on the ground glass, and the plate used in the dark slide being a lantern plate. Thus it will be seen that it is possible to copy any size of negative, however large, and make a slide 3 1/4 in. square to fit the lantern just as easily as one from a small negative. Some workers assert that slides made by contact are never so good as those made by reduction ; and if care is not used in the contact method much may be lost in sharpness, but perhaps a good deal of what is put down to superiority is not so much technical merit as a certain artistic quality. I have failed after repeated tests to discover any technical difference between a slide made by contact and one made by reduction, the same subject and exactly tlie same portions of the negative being used in each case.
There are cheap pieces of apparatus for daylight use upon the market for reducing negatives to slides which will save the worker endless trouble; they are most efficient and speedy in use, and are to be recommended to any who can afford the few shillings they cost.
For reducing by artificial light more expensive apparatus is needed, on account of the condenser being required. A simple plan is to have two camerasóa large one to hold the large negative at one end, and a small one to hold the lantern plate. Place the two on a long board, remove the lens from the larger camera, and through the hole thus left point the lens of the small camera. Now place the big negative to be reduced in the dark slide, and place it in position in the big camera, and draw both shutters. Adjust the whole board to the light and photograph the big negative with the small camera, using a lantern plate for the purpose.
Development is the same as in the case of contact slides, which has already been described.