International photographer (Feb-Dec 1929)

Thirty-eight The INTERNATIONAL PHOTOGRAPHER December, 1929 Peeping in on Par/in BY ARTHUR REEVES, 659 Arthur Reeves A trip through the DuPont-Pathe Film Manufacturing Company plant at Parlin, New Jersey, would do any cameraman's heart good. The Parlin plant is just one hour from New York and nestled in the low rolling hills of New Jersey. When the writer arrived he was met by Doctor Sease and we proceeded at once to the plant. At the gate we were divested of all matches before we could enter and then went to the Redpath Laboratories. This building houses the Technical Staff and Research Laboratory. I will endeavor to give a cameraman's view of how motion picture film is made at Parlin. During the morning session I was taken through the plant by Mr. G. A. Scanlan who certainly knows the why and wherefore in film manufacture. The Dope First we went through the dope department and witnessed the making of the celluloid base. At the dope mixing plant we find the nitrated cotton which consists of small wads of cotton kept damp with alcohol because, in a dry state, it is very explosive. This nitrate cotton is placed in large mixing machines with acetone and other solvents and the cotton is dissolved. The result is a thick syrup known as nitro-cellulose. This dope is forced through filters, then into storage tanks and then into vacuum tanks that remove all the air so there will be no air bubbles in the finished film base. The Casting Machine The casting of film base is a very interesting process inasmuch as the dope goes in one end and comes out the other end a roll of celluloid. The dope runs into a hopper which spreads the liquid on the casting wheel with exact precision. The casting wheel is 15 feet in diameter, 50 inches wide and has a perfect surface which is highly nickel-plated. As this wheel revolves slowly, but constantly, the hopper spreads the dope upon it at the desired thickness. The dope adheres to the wheel and as it revolves it sets itself and is peeled off just before the revolution is completed. It is then passed over rollers for further drying. The casting wheel is encased and the fumes are drawn off and the solvents and acids are regained. As the large strip of film base passes toward the end it is immersed in a liquid sub-base which adheres to one side of the film. This sub base enables the emulsion to take hold during the coating process. The film base is then wound up in rolls 50 inches wide and stored away until ready for coating. The casting machine runs constantly day and night and never varies the temperature more than one degree. Emulsion Making In the making of the panchromatic emulsion lies the success of Dupont negative film. The Redpath Laboratories and their research department, headed by Doctor Sease and assisted by H. W. Moyse and D. R. White, have done wonders in the making of panchromatic emulsion. The nitrate of silver used in emulsions is not very sensitive ti light until mixed with gelatin. After these two are mixed with bromides, etc., the mixture is allowed to solidify in large pieces. These large pieces of emulsion are put into a machine and pressed through a screen, coming out in strings like noodles. These noodles are then put into small containers and washed for a certain period of time. The washing of these noodles has to be done with caution as this process controls certain qualities in the finished product. The noodles, after washing, are put in the ice box until needed. This part of the process is done under the red light. To make the panchromatic emulsion the noodles are put into a large kettle and melted and mixed at 90 degrees. Now comes the important part — the mixing of the dye which makes the emulsion panchromatic. As soon as the dye is properly mixed and the emulsion is at the proper viscosity it is run over to the coating machine. The dye used in this emulsion was developed in the Redpath Laboratory. From the mixing point on, everything is handled under the Green safe light. The Coating Machine The coating of emulsion on the film base is a very important step in film manufacture. The film base is coated in rolls 50 inches wide and in lengths up to 4000 feet. The film base is passed over rollers with the sub-base side downward into a constant level tank and is emersed the right depth so that the emulsion will not get on the reverse side of the base. The liquid emulsion is at the proper temperature and viscosity and as the film base passes through it adheres to the sub-base. The speed at which the film base passes through the liquid emulsion determines the thickness of the emulsion upon the finished film. As the film travels up from the emulsion tank with the wet emulsion sticking to it it passes into a chilled chamber which is very cold and sets the emulsion. From here it passes over rollers into the drying tunnel which is 350 feet long and is then rolled up in large rolls for the slitting department. The coating machines are shut down every few days for thorough cleaning as we all know that dirt or dust is a bug-bear in motion picture film. The Finished Product The rolls of film coated with emulsion are sent in to the slitting department where it is cut into the right width and length. The film then goes into the perforating department and then into the inspection department. Here the film is wound into rolls for packing and during this process the emulsion side is inspected by light reflected at an angle that will show any defect. The film is then packed in cans and labeled for shipping. The Afternoon Session The writer was turned over to Doctor Sease who proceeded to explain the technical and scientific side of film manuture. In every step of the making of film there are exhaustive tests to be made. These tests were explained by Doctor Sease. First the dope is tested before casting and the film base is constantly watched for scratches and other defects. Then the emulsion has many tests before coating and as soon as coated every roll is tested at each end before it is O.Ked for slitting. Now the real testing starts. The film is given the well known H and D test and Photometer tests and tests for speed and color values as well as comparative tests with previous emulsions. Then there are static tests, tensile strength tests and no end of perforator tests — in all about 15 separate tests before the film can be put into the can. There seem to be no deep secrets at the Dupont-Pathe Film Manufacturing Company's plant at Parlin and one is impressed with the readiness that questions are answered and processes or machines explained. But, after all, what can a layman learn going through a great industrial plant like Parlin in one day. W. E. OPENS LAB. The formal opening of a new engineering laboratory by Electrical Research Products for research and experimental work on talking pictures as a service to producers using the Western Electric recording systems recently took place in Hollywood The laboratory is equipped with a complete one channel film and disc recording system, sound proof recording studio, a review room for the showing of talking pictures, developing and printing equipment and many other machines and apparatus for the study and perfection of talking equipment and production technique. The laboratory is another step by Electrical Research Products in rendering immediate service to help them solve problems of recording which continually arise in their efforts to further the art of talking picture production. According to J. J. Lyng, vice president of Electrical Research Products, who attended the opening, the motion picture industry is a creative one and every new picture puts the recording system to a different use than the preceding (Continued on Page 41)