American cinematographer (Oct 1937)

October, 1937 • American Cinematographer 435 AUTOMATIC DEVELOPMENT AND ITS ADVANTAGES T wenty-five years ago ail 35mm. professional motion pic- ture negative and positive were developed by the “rack and tank” method, a system in which the film was wound on a rack and then in- serted in tanks for the various proc- esses of developing. Then it would be rewound off the racks on to a big drum that revolved until the film was dry. This was a long, laborious proc- ess that left much to be desired. If in the process the laboratory technician forgot to take a rack of film out on time the picture suffered; or if it came out too soon it was just as bad. And then, too, there would be fingermarks, scratches, digs and dust added while the film dried on the big whirling drum. Many more things happened due to the handling and rehandling of the film. Today, except in the instance of one major manufacturer of 16mm. ama- teur reversible film who has perfected automatic machines for his own ex- clusive use, the majority of amateur film still is processed by the same antique method of early day movies. For a long time it has been known in the trade in Southern California there was in operation a 16mm. au- tomatic machine—for three and more years, in fact. Then last April Walter W. Bell, the manufacturer of the one just mentioned, began work on a second. This was completed nearly three months ago and was installed in the plant of the Hollywoodland company, in South Gate, several miles from Hollywood. It has been in full opera- tion and successfully ever since. Automatic Operation While these automatic developing machines usually are surrounded with genuine secrecy this reporter was given an opportunity through the in- vitation of Walter Bell and the court- esy of Ben Doty to see the newer one in operation. These machines take the film in at one end, develop it first as a negative and then re-expose and redevelop it as a positive. Then the film is washed, dried, polished and wound ready to be run on the projector. All this is automatic and continuous in operation. The newer machine is installed in Story of Actual Operation of Machine That Processes Amateur Film Without the Hazard of Handling Injury a room about 24 feet long, the device taking up about two-thirds of the space. In what is termed the “wet end” there is a large tank approxi- mately 36 inches wide by 36 inches deep by 7 feet long. The tank is divided into nine compartments, each one accommodating the particular solution necessary in the processing of reversible films. Suspended immediately above the tank by means of cables and counter- weights was the mechanism that car- ried the film over a series of rollers through the various tanks. The mech- anism contained nine separate units, one over each tank. Each unit carried twenty rollers across the top and nineteen at the bot- tom. A drive shaft led down from the main frame to the bottom rollers of each of the nine units, and was so constructed as to drive the bottom rollers. A continuous length of clear film leader was threaded over these rol- lers from top to bottom across each unit and then on to the next unit, and so on until it came out at the ap- pointed end. By means of a gear this entire mechanism is lowered into the tanks, one unit into each of the nine compartments. Completes Process With the film and mechanism now submerged in solution a two-thousand- foot reel of exposed film is stapled to the end of the leader film, a switch is snapped on and the film is started on its way winding over and over through the first set of rollers in the first tank. It soon reaches the end of the first developer. Then it crosses over the last top roller and into the next tank, a wash tank. On and on it goes, back and forth from tank to tank, until it has com- pleted its run through the “wet end.” Now, completely processed, it passes into the dry box, a completely in- closed glass case, 3 feet wide, 6 feet long by 7 high. Here the film again passes over another series of rollers, there being four tiers in all. The thread-up in this end is ample to allow the film to dry. By a driven take-up it is wound on a 2000-foot reel ready to have each roll separated and returned to the respective owners of each roll. The machine is so arranged that it can run continuously until the entire day’s work is done, provision being made to splice on additional reels of exposed film at the feed-in end with- out stopping. Likewise full reels can be removed and replaced with empty reels at the take-up end with- out stopping. One of the “bugs” that had to be ironed out in the building of the ma- chine was ascribed to the fact that acetate base film after being wet stretches from three to four feet to each hundred. With a thread-up of over 1000 feet in the wet end it may be easily seen some means of taking care of an additional thirty to forty feet of loose film must be made in the wet end of the machine. Shrinks Back in Drying During drying the film again must shrink back to its normal length, or pitch, so again in the dry box the mechanism must allow for this shrink- age or the film will break. Previously we have mentioned the film is driven through the entire ma- chine by the lower rollers and not the top rollers. In this lies the secret of compensating for stretch and shrinkage of the film. Immediately when the film starts to stretch in the wet end it tends to fall away from the bottom rollers, which nat- urally slows the speed of the film at that particular place. This slack is then transmitted to the next rollers back, and so on, thus never allowing an undue amount of slack to accumulate in one place. The same process applies to the points where the film shrinks, for as it tightens the rollers drive to full speed identical to the speed it is fed into the machine before the film stretches, thus preventing it from breaking. High pressure airvalves blow the excess solution off the film as it passes from one tank to another. Also air is used to dry the film, both emul- sion side and back, before passing into the dry box. The result is that the finished film needs no polishing and is assured of being perfectly clean. In the dry box, which is air tight,