Motography (Jan-Jun 1914)

April 4, 1914. MOTOGRAPHY 239 Motion Picture Making and Exhibiting By John B. Rathbun CHAPTER VIII {Continued.) THE whole of the mechanism outlined in Fig. 59 is carried by one of the pantograph bars so that the arrangements made to vibrate N in no way effect the movement of the latter as the reproducing style of the pantograph. A blank film is clamped beneath iV and, on proceeding as above, there is punctured on the stencil film a series of very closely adjacent holes which mark out the actual size and position of those portions of the positive film which the operator has selected for red coloration. This being done, the positive and the stencil films are moved forward one picture-pitch by a simple wheel and ratchet gear and the operation is repeated. Finally, the detachable portions of the stencil are cleared away by aid of a pointed style and the finished stencils (and the pieces removed), present the appearance shown in Fig. 60. The beautifully sharp edges of the stencils are remarkable. One stencil is cut for each color to be applied to each picture so that, for a three-color film 48,000 and for a seven-color film 112,000 stencils have to be cut for each 1,000 feet of positive film. To dye films for exhibition is a simple matter once the stencils have been cut. The film is pressed in close contact with the stencil and is passed beneath an automatically-fed dye-band. Thick aniline dyes are used and the film can be passed direct on to the receiving spool without preliminary drying. The whole dyeing machine is driven by a 1/3-1/4 h.p. electric motor and the film is passed through it from three to seven times (according to the number of colors selected), the appropriate dye and stencil being used in each case. Usually about 100 films can be made from one set of stencils before the latter begin to show signs of wear. This, briefly, is the process by which Pathe-color films are prepared and we have described it in some detail since it is as ingenious as it is successful. DIFFICULTIES OF COLOR PHOTOGRAPHY Even with the photographic system in which each color is recorded by a separate picture, the production of color is attended with great trouble and expense, so great, in fact, that there are at the present time but few systems that have proven a commercial success. Peculiar mechanical and photographic factors as well as lighting and physiological difficulties, not understood by this chapter — where it will be remembered that the coloreffects depend entirely upon the persistence of vision. Two colors, red and blue-green, supplied by two filters, supply the entire range of effects, and without overlapping, as in the Friese-Green system. Whatever intermediate tints are produced are caused by overlapping the pictures mentally. The film itself is black and white, similar in appearance to an ordinary film, and is projected at about two and one-third times the speed of the black and white film. As a result of this speed the projectors are always driven by a motor, for the work is far beyond the capabilities of the ordinary operator. A panchromatic film is exposed by a double shutter camera that throws the light from red and green filters alternately. The pictures thus produced extend down the center of the film in a manner similar to that of an ordinary film, except that the pictures are alternately taken through red and green filters. To distinguish the green pictures from the red, a small green dot or dash is stamped on the margin opposite each green picture, so that in case of a break the film may be patched in the correct relation. In projecting this film the beam of light passing through the successive pictures is alternately colored red and green by a shutter that also acts as a filter. The green blade comes before the beam when a green picture is in the aperture, and the red blade enters when a red picture is in the aperture. As the pictures are on a single strip of standard film, it is necessary to use only a single lens, and for this reason it is possible to run an ordinary black-white film in the same machine by cutting down the speed and by substituting an ordinary shutter. Kinemacalor films require much more light than the ordinary film because of the intervention of the colored shutter. Figs. 59 and 60 — Pathe Stencil Cutter. The shutter is a circular disc with two color windows of gelatine, one red and one green. The ordinary opaque shutter used for blacks and whites is left on the shaft with the color shutter and serves to shut off the light when the open spaces between the color sectors pass the lens. A single thickness of gelatine is used in each sector with a second sector thickness on the green that occupies about one-half the space of this sector. The purpose of this additional thickness on the green sector is to regulate the relative proportions of the red and green light. When the volumes of the red and green light are correctly proportioned, a perfectly white light will be produced when the shutter is rotated without film in the aperture as red and green are complementary colors. gaumont's chronochrome. Gaumont, the French film producer, has recently devised a direct color photographic system that is said to be greatly in advance of any similar device on the market. From the reports of European technical experts, the inventor has completely overcome the loss of color register and illumination that have been the despair of other experimenters. Because of the late development of the camera and projector it is impossible to describe the mechanical features of either the camera or the projector. The technical expert of the London Bioscope in a