The Moving picture world (July 1926-August 1926)

190 MOVING PICTURE WORLD July 17, 1926 that is, the reg-orange-yellow series of pictures, on a strip of this specially thin positive stock. Correspondingly on another strip of this positive stock the blue-green alternate series of pictures is printed from the' negative. By means of the accurate perforations it is possible to bring these two strips into register, which is done in the technicolor process in a machine which also functions to cement the strips together. The cementing machine uses a solvent which softens the two films sufficiently to weld them together, and is epecially designed for the purpose. We thus have at this point in the process an undeveloped double-coated positive film each frame of which comprises a latent image of the green-blue picture on one side, and on the other side a latent image of the red-orange-yellow picture, these two being geometrically identical and in absolute register. This film is then sent through specially made developing machines which are automatic and which, by means of suitable chemicals, baths, etc., transform the latent images into relief images. With the ordinary developing processes these images would appear as black silver deposited corresponding in density with the light from the object photographed. The function of the Technicolor developing machine is to harden the gelatine wherever there would have been such a silver image and to leave it soft wherever there would not have been such an image, and to dissolve off the soft portions of the gelatine. In this way there is left a relief image of hardened gelatine, that is to say, the gelatine left has a thickness from point to point just in proportion as there would have been a silver image by an ordinary developing process. Now Comes The Color After drying this double-coated relief image positive it is sent to the coloring machines. In these coloring machines the gelatine relief images take up dye from point to point in proportion to their thicknesses so that by this step there is put back into the film the color values just in proportion as they existed in the relief image. This final colored film is given a very thin protective coating and is then ready for projection. The resulting pictures on the screen are extraordinarily beautiful and faithful. Projectionist ! Pointers Technicolor film requires no special machinery, equipment or attachments for its projection and is shown in theatres all over the world, using the standard black and white projection machines. Structure and Properties Of Film In order to understand how to project Technicolor film properly it is necessary to know something about its special properties, how it differs from ordinar.v "black and white" motion picture film, as well as to what extent it resembles the latter. The outstanding special feature of Technicolor film, which everybody recogTiizes, is of course the fact that the pictures which it produces upon the screen are in full natural color, instead of being in monotone or some unnatural combination produced by tintingand toning. A close examination of a piece of Technicolor positive film will show that it has a gelatine coating on both sides, instead of on a single side as is the case with ordinary "black and white" films. Thus, its general structure is somewhat similar to that of socalled N. C. (non-curl) Kodak film, which has a hard transparent coating of gelatine on the back. However, the coatings on both sides of Technicolor film are similar to one another, except for one thing: a difference in color. One side is red and the other is green. It is difficult to appreciate this fact under ordinary conditions of observation because the two colors combine with each other to yield the natural colors of the scenes which the film represents. However, if one side becomes deeply scratched, the color of the opposite side is clearly visible. The gelatine coatings of Technicolor film differ from the single coating of ordinary black and white film in that the former vary in thickness from one point to another of the film surface. In fact, it is this variation in thickness which forms the image or picture. Where the gelatine is thick the color is strong or the density great; and where it is thin the color is weak or the density is low. There are some points on the film where there is no gelatine at all, or practically none. Both edges, on both sides, over the sproket hole region and up to the picture frames are thus free from gelatine. This freedom from gelatine coating on the edges has several advantages. It makes it unnecessary to wax or otherwise to lubricate Technicolor film before its first running in a projector. It also increases the life of the film since brittleness in film is largely due to the gelatine coating, particularly when this becomes dry and hard, as it does with age. The Proper Projection of Technicolor Positive Every good projector operator knows that in order to give a first class show he must keep the picture in sharp focus on the screen at all times. This is especially true of pictures in natural colors, in which the snap and realism is seriously impaired if the screen image is allowed to blur. Now the focus for Technicolor film is frequently — and probably as a rule — slightly different from that ot black and white film. This is due partly to the presence of the color, but mainly to the difference in structure between the two kinds of film, as already explained. To yield the sharpest picture on the screen MACHINE SPECIAL ROLL and TICKETS Your own special Ticket, any colors, accurately numbered ; every roll guaranteed. Coupon Tickets for Prize Drawings: 5,009 for $7.00. Prompt shipments. Cash with the order. Get the samples. Send diagram for Reserved Seat Coupon Tickets, serial or dated. ROLL AND MACHINE TICKET PRICES Five Thousand $3. SO Ten Thousand €.00 Fifteen Thousand 7.00 Twenty-five Thousand f.OO Fifty Thousand 12.50 One Hundred Thousand IS.ti National Ticket Co. Shamokin, Pa. the lens must be focused half way between the two gelatinee surfaces of Technicolor tllm, while for the best results with black and white it must be focused on the single surface which carries the emulsion coating. Furthermore, the exact degree of curl of black and white and of Technicolor positive is apt to be different so that the two films do not lie in exactly the same plane in the gate of the projector. It follows from the facts just stated that it is usually advisable to readjust the focus of your projector when passing from black and white to Technicolor or vice versa. It will repay any operator to make this extra effort to insure for the audience an experience of the full beauty and sharpness which is really present in the film. Differences in focus are also found between different rolls of black and white film, and the alert operator will always be watching his screen for the best possible results In any case. Cupping Its Cause When Technicolor positive becomes quite old it may show a considerable degree of "cupping," which makes It difficult to maintain a steady focus at any setting of the lens. Film in this condition should be returned to the Technicolor laboratory for renovation. Distributors who have had a great deal of experience with both Technicolor and black and white film report that cupping Is ordinarily worse with the latter than with the former. However, it is possible that the greater stiffness of Technicolor film may cause a cupped sample to behave worse in a projector than will an equally bad sample of black and white. The adjustment of the projector itself will have a great deal to do with the matter. Film in a cupped condition will run more smoothly with an increase In spring tension in the gate of the projector. Since Technicolor positive has a gelatine coating on both sides instead of on only one side. It is evidently important to protect both faces of the film from mechanical damage, such as scratching. A light scratch on Technicolor film will show on the screen as a dark line just as in the case of black and white; but a heavy scratch will show as a bright line of red or green. This is because the color has been removed bodily from the scratched side and the complementary color of the opposite side shows through. If you see a red line or spot on the screen you may know that the green gelatine has been Injured, and vice-versa. The most Important causes of such scratching are oversize loops, guard plates or other devices which bear upon the celluloid face of black and white film, dirt in the aperture or elsewhere, etc. In general, a thread-up and condition of the projector which Is absolutely first class for black and white is O. K. for Technicolor. No Careful operator will permit even the celluloid side of a film to drag on any portion of his machine, since celluloid side scratches when they occur, are no more beautiful than are those on the gelatine side. Some projectionists under some circumstances may find difficulty in deciding which face of Technicolor film to thread up towards the lamp house. The correct position can of course be determined at once if a title is available, since this must obviously be threaaed so that the words read from left to right San Francisco Bits EDWARD H. KEMP, pioneer theatre equipment and supply dealer, with quarters at 309 Turk street, San Francisco, Cal., has added to his interests the Ball Film Laboratories near by. He is continuing the supply and equipment business along former lines and will maintain two places of business. TYPHOON COOLING SYSTEM I I TYPHOOH FAN CO. 1* 345W.39-ST. NEW YORK