The printing of aerial negatives may be done either on roll or cut paper, and if films are used, a further alternative is offered of handling it either in the roll or in cut form. Where many prints are to be made from one negative roll paper has some advantages, particularly if a developing and drying machine is available. But for moderate numbers the advantage is small, since cut prints can be developed quite conveniently in goodly numbers in the ordinary trays. But the advantages of keeping film in the roll form are very great, both in respect to storage and in respect to handling during printing, as the rollers provide the necessary tension and prevent the film “getting away.” [Illustration: FIG. 119.—Interior of McIntire printer, showing lamps adjustable in position for “dodging.”] [Illustration: FIG. 120.—Film printing machine.] For the American Air Service, cut paper has been used exclusively. For film printing, the Ansco machine has been equipped with roll pivots to take film 24 centimeters wide which may be advanced in either direction by turning large milled heads (Fig. 120). If we put rollers on the two remaining sides of the box to handle paper we transform the printer into the same form as a French machine, in which paper and film are moved at right angles to each other. A disadvantage of this modification, however, is the difficulty of examining the negative to be printed. =Stereo Printing.=—To make separate prints from the two elements of a stereoscopic pair and mount them side by side after proper orientation is too slow a process if quantities of prints are needed. One method of multiple production is to make a master stereogram, and then produce photographic copies of it, but there is inevitable loss of quality in this copying process. An intermediate method is to print from both negatives on the same sheet of paper. In order to do this the negatives must be placed in rather large frames, with mats properly located to guide the placing of the paper. The Richard double printing frame is a practical device which simplifies the necessary manipulations. It consists essentially of a platform pierced with three illuminated openings. The two negatives are compared, superposed, and orientated over the central opening and then shifted laterally, one to each of the two side openings, which serve both as printing frames and masks. The printing back slides on a rod, permitting the paper to be lifted up and moved between exposures. Once the negatives are properly placed, stereo prints can be turned out quickly and easily.