The Cine Technician (1939)

17.1 T UK C ] N E-T E CH NIC I \ \ I > .1 in.. 1937-8 OPTICAL PRINTING and OPTICAL PRINTERS By ALFRED C. SKITTRELL OPTICAL printing, or projection printing, as it is sometimes called, is a process oi rephotographing from one film to another at unit magnification. The apparatus necessary consists of a cine camera with a registration movement and a printer head (or projector) also with a registration movement, mounted upon a lathe bed so as to face each other. The camera, its lens, and the printer head are mounted upon separate sliding stands, adjustable by hand, and both vertical and lateral movements are usually provided for all three. Accurate registration is of the utmost importance. Lining up for exact registration is difficult if it depends entirely upon a scale or indicator of some form, no matter how fine the mechanical adjustment may he. A better and safer method is to use a target film. This consists of a pattern oi lines photographed on to cine film, and when a piece of this is placed in the projector and its image projected on to a similar piece placed in the camera, the correct setting for exact registration becomes appaii nt when the two exactly superimpose. Optical printing is utilised for an endless variety of work. Full control of duplicating print and negative stock is possible at all times, permitting a very great degree of manipulation. Many effects formerly produced in the camera such as fades, dissolves, matte shots and split screen and composite scenes are now made on the optical printer, and in addition an entirely new range of trick effects such as wipe-offs and trick transitions has been made possible. Tin; production of fades and dissolves is relatively simple. A print is run through the projector and copied in the camera, while the camera shutter is manipulated to effect fading. Wipe-offs are a little more complicated and there are several ways of producing them. One is by means of a mechanical device, geared to the camera drive so as to move as the film runs through, the direction and speed of the movement having been prearranged. With this method only a limited number of effects are possible and the more usual method is to use film mattes or masks. These allow a much greater variety, Figure i limited only by the ingenuity of their devisors and the means at hand to produce them. The required pattern is worked out step by step, in black and white or in light and shadow, each step being photographed. A print is taken from the negative so obtained and the wipe-off effect is produced by running first one and then the other of these two film masks through the projector, while the duplicating print is running through the camera, in contact with the negative raw stock, a bipack magazine being used. (Fig. 1). Before the advent of the optical printer, many special effects were made during the primary filming, ghosts or visions, glass shots, matte shots, in fact everything to make the cameraman's life unbearable and to waste time and pile up costs. All such work can now be done upon the optical printer. In fact it can safely be said that the optical printer is definitely one of the most flexible tools at the disposal of the film-technician. One very important factor in optical printing is firstclass quality in duping and laboratory manipulation plays an important part in attaining this. The slightest variation in the standard is felt more by the optical printing department than by the production department owing to the fact that the dupe neg must match the original. In production there are three basic laboratory processes, viz : 1. Developing the original negative. 2. Making print from original negative. 3. Developing print from original negative. In opitical work there are five, viz : 1. Making Duplicating Pos. 2. Developing Duplicating Pos. 3. Developing Dupe Neg. 4. Making print from Dupe Neg. 5. Developing print from Dupe Neg. Obviously the margin of error is greatly reduced, and successful results demand intense laboratory co-operation. Having arrived at a satisfactory routine of duping to fit existing conditions, consistency of laboratory work is vital if good results are to be continuously achieved. First in importance is the making of the lavender duplicating print. Obviously, without a good master the duplication of the original is impossible. Strict sensitometric control is imperative. A too soft or too light print will give a too flat neg, and conversely a too hard or too dark print will give a too contrasty neg, and in the case of a too dark print, an increase in graininess. Slight variations can be compensated for, but this, of course, means a departure from the established routine and, in addition, uncertainty as to results must exist until those results have been examined and tested. This importance of the duplicating print cannot be too strongly stressed. Indeed, it is safe to say that unless it is exact, true duplication of the original is a practical impossibility. From the mechanical point oi view, the quality o\ the dupe is affected by three things: 1, the lens; -. evenness of light ; 3, uniform speed in running. Besides the regular cine lenses, there are copying lenses on the market which give quite satisfactory results. A focal length of from four to six inches allows comfort (Continued on page 1771