 Upon completion of the photographic mission, the film must be processed. On this mission, a T3A camera has been used. Consequently, the entire camera must be removed to the laboratory dark room for unloading. The exposed film spool is removed from the camera. The loose end is taped and the film placed in its original container until such time as development can be accomplished. The B3A film developing assembly is standard equipment to the air core. This assembly consists of three nesting non-corrosive metal tanks, a spool assembly to hold the film, a motor to transfer the film from one spool to the other during the developing process, and a loading plate used in loading the assembly. In using this apparatus for developing, the following operations are performed. Place the exposed film spool in place on the loading plate. The end of the film is inserted in a slot in the developer assembly spool and secured by means of the small spring retaining latch in the top of the assembly spool. Transfer the film from the camera spool to the developer assembly spool. Cut off squarely the tapered end of the exposed film and secure this end in the same manner as the other end of the film. To facilitate this operation, the assembly may be placed horizontally on the table. Load the assembly so that the film may be transferred from one spool to the other with the emulsion to the outside of the spool and unobstructed by the assembly support rod. Before the unit with the exposed film roll is placed in the developing solution, it is generally best to immerse it in clean water and transfer the film from one spool to the other once or twice to eliminate air bells or bubbles. After immersing the wet film in the developing solution, quickly transfer the film from one spool to the other by hand and retransfer to the original spool. This rapid transfer from one spool to the other ensures even development of the negative. The motor drive unit can now be placed on the film spool assembly and set in motion. When all of the film has been transferred from one spool to the other, the tension created by the fastened end of the film automatically reverses the direction of the drive unit. The entire unit then tips, and the motor drive engages the empty spool and repeats the transferring process. The processing tanks must be reasonably level or the motor unit will not function properly. After the film has remained in the developing solution the required length of time, the excess developer should be allowed to drain off before immersing in the rinse water. Here again the film is transferred from one spool to the other by hand to eliminate the greater part of the developing agent. Transfer the assembly from the rinse water to the hypo solution or fixing bath where proper agitation must be maintained for a period of at least 30 minutes. The film must then be transferred to the wash water where all traces of the hypo are removed. Here again the film should remain in running water and be agitated by the motor drive for another period of 30 minutes. From the wash water the film is taken immediately to the film dryer. Here the entire assembly is placed in the tray on the front of the dryer. This tray should contain clean water to rinse the film immediately before it goes on the drying drum. Place the metal lead clip on the end of the film. This metal clip serves as a guide for the film as it passes over the rollers on the drum. Thread the metal film leader over the first film roller and start about 8 or 10 inches of the film down between the rollers and the slits in the outside of the drum. Start the blower on the drying drum and carefully guide the film onto the lead rollers. In the drying process the film makes one complete revolution of the drying drum and will be held tightly to the rollers by the air from the blower and will be propelled around the drying drum between the rollers and the air slits in the outside of the drum. After the film has passed completely around the drying drum, the metal leader should be taken off and a folded end of the film removed. Thread the dry roll of film under the take-up spool and fasten the end squarely to the spool with two short pieces of adhesive tape. The film will now be automatically wound under the take-up spool with the emulsion to the inside of the roll. After the film makes the complete revolution of the drying drum, it is wound in a metal spool on the same side of the dryer on which it was inserted. The dry film is then ready to be lettered in conformance with air core circular number 95-3. Place the roll of negative on the front of the lettering table and feed the end of the film under the straight edge to the take-up spool on the far side of the table. Lettering is accomplished with India ink and a lettering pen on the glossy side of the negative. Each negative should be lettered in the lower right-hand corner. The information should consist of the type of picture, location, organization number, date and time of day, focal length of lens and altitude. If the project is a mosaic job, sufficient paper of the same emulsion number should be on hand to complete the entire project. Printing all the negatives on paper of the same emulsion aids materially in maintaining the same degree of contrast in the finished prints. The photographer should therefore set aside this required amount of paper until such time as it is needed. Enough developer should also be mixed at one time to complete the work. This should be diluted to the standard proportions with water and the proper temperature maintained. Place the roll of negatives in the printer in such manner that the emulsion side of the negative will be in contact with the emulsion side of the paper when the print is made. Place the paper in the printer with the emulsion side toward the negative. Several prints should be made at the same time so that they may be developed together. In printing negatives from the T3A camera, the B7 printer is used for the oblique photographs. The necessary correction in scale is made by projection printing and the prints developed in the same manner as the contact prints. Immerse the prints in the developing solution and make sure that all air bells and bubbles are broken when the paper is immersed. In developing a number of prints at the same time, the degree of contrast to which the prints are being developed can be compared and controlled with a much greater degree of accuracy than by the development of each print separately. When the prints have been developed to the proper stage, they should be immersed in the shortstop solution and then placed in the hypo-fixing batch. From the fixing batch solution, place the prints in the wash water. Here they should remain at least 30 minutes to remove all traces of the chemicals and to ensure the permanency of the prints. The photographer should maintain the strength of the developing solution by frequent addition of fresh solution. Drying the prints is usually accomplished by placing the wet paper prints on a canvas belt which rotates around a heated drum. The photographs made by the T3A camera are mounted either by the use of an adhesive or by the use of staples. The completed prints for a mosaic are matched for contrast so that a maximum degree of uniformity may be obtained in the finished mosaic. In the preparation of a mosaic, a control network is first plotted on a military grid of sufficient size for the project. These known points are obtained from existing surveys, United States geological survey sheets, road maps, or triangulation points set up especially for the project. The known points are carefully plotted and plainly marked on the grid so that the photographs may be accurately mounted. In mounting the photographs on the grid, the first step is to match the photograph for contrast and to check the scale with the photograph to which it will be adjacent. Next, trim the edge of the photograph with a razor blade, being careful just to cut through the emulsion and not all the way through the paper. Now the trimmed edge should be folded back away from the emulsion. Thus, by tearing this trimmed edge away from the operator, it will be found that a feather edge has been created on the print to be mounted. This rough edge should be smoothed with sandpaper. Thoroughly cover the back of the print with adhesive and carefully place the photograph on the mountain. Roads, streams, or wooded areas can be used to match the prints. Excess adhesive may be removed by a bone squeegee. To correct local areas on the mosaic, portions may be trimmed out of photographs which match that area and mounted in the same manner as the original photograph. The completed mosaic is delivered to the interpretation officer who translates its images into the desired information. By the use of the stereoscope and a finished mosaic, much useful data may be obtained such as new enemy gun positions, troop movements, new trench excavations, and camouflage. Close cooperation between the photographic unit and the interpretation officer is essential.