American cinematographer (Jan-Dec 1941)

j UNCLE SAM'S 300 MPH FLYING LABORATORY By REED N HAYTHORNE, A.S.C WHEN the U. S. Army Air Corps orders pictures, speed is the watchword in more ways than one. Today the Army's flying photographers can expose, develop and print tactical stills, while streaking through the air at 300 mph. on observation missions. Officials of the Air Corps Photographic Research Laboratory at Wright Field, Dayton, Ohio, under the direction of Major George W. Goddard and Project ; Engineer John Hancock, have devised methods of photographing, developing and printing a picture in an airplane so i speedily that the finished print may be I dropped from the airplane within four I or five minutes of the time the shutter ! clicks. The military advantages of this quick photography process will be obvious in these days of mechanized attacks and blitzkriegs. Suppose a ground-troop concentration in the field is expecting an attack from an enemy on its right flank. ■ Suddenly the commanding general is adj vised that the enemy is concentrating : mechanized units on his left flank for a surprise attack at that point. Prompt, accurate information as to the truth of this report is vital. And it must be in his hands quickly, so he can dispose his troops to meet the new threat before the blitz has time to develop! Radio directs observation planes to obtain quick photos of the enemy's dispositions in the questioned area. Within a matter of minutes the finished prints are dropped at field headquarters, and the general has definite proof, substantiating or disproving the second report. Using the Air Corps' equally new flashbomb technique, these photos can even be brought back on the darkest night. Using the quick photography method, Air Corps cameramen can also supply a definite photographic record of the effectiveness of long-range artillery within a few minutes after a salvo has been fired. And the photographers also can locate targets far out of sight, but within range of the big guns, by spotting them in photographs in relation to known landmarks. Most important factors in the Air Corps quick photography method are: (1) a compact processing tank with four compartments which may be installed in Washington Staff Correspondent any Air Corps tactical ship larger than a single-seat pursuit plane; (2) a special type of cut-film holder designed by the photographic laboratory which is used continuously as a camera holder and as a processing holder; and (3) a small but highly efficient printer operated in a light-proof zipper bag. The Air Corps has tried the direct positive or reversal method of photography in which the picture is taken on a piece of photographic paper, which when developed, itself becomes the finished print. But the Air Corps experts have discarded this method, at least for the time being, and have gone back to the conventional method of exposing a negative and then transferring the image to a positive print. It was found that the direct positive was extremely limited in its emulsion latitude. It could be used only under favorable daylight lighting conditions, and even then the exposure had to be just right. With either a bad overexposure or underexposure, the picture was lost. Now the Air Corps photographers frequently have to work under unusually difficult conditions when they want early morning or late evening pictures. Wars don't wait for ideal picture-making weather-conditions! So the research men have returned to the orthodox method. But they are still experimenting with direct positives in the hope of producing an emulsion which will make the direct positive process usable under wide latitudes of lighting conditions and exposure. Let's follow Wright Field cameramen and see how they make a "quick photograph." They take off and fly high over an airport which they have selected as their pictorial objective. The pilot swings the plane over the objective and the cameraman "fires" his 20 or 40-inch telephoto lens camera, designed for making oblique intelligence photographs. Incidentally, he doesn't have to focus his camera. He is far enough away from the ground so that the camera has a fixed focus, at infinity, except for infra-red film where a special infinity focus is required. So all he has to worry about is exposure and lens opening. As soon as the exposure is made, he takes the holder from the camera and immerses it in the first section of the tank. He pulls the slide up out of the holder so that it sticks up above the tank and uses this as a handle to agitate the holder in the tank so that the negative is fully treated in the developer for one minute. Replacing the slide, he removes the holder and transfers it to the second section of the tank, where it gets the same agitating process for 15 seconds, in a stop bath solution. The negative then gets 75 seconds in the third tank, a fixing solution, and a 5 second water rinse in the fourth tank. Incidentally, each section of the tank has a nonspill lid, so that the plane can do any ordinary maneuvers without spilling chemicals. And the tank is jacketed in an insulation material one and onehalf inches thick, which is electrically heated to a constant temperature of 75 degrees. After its rinse, the negative is quickly sponged off with a rubber squeegee, to remove extra moisture, and is then ready for printing. It is placed on the printer contact surface, and covered with a sheet of transparent material, to keep the printing paper from getting wet. The sensitized paper is taken from a container and placed over the negative, and the lid is brought down to make the exposure. To the trained photographer there is ordinarily nothing unusual about this procedure — but it must be remembered that the quick-work photographer has his arms thrust into that black zipper bag, and is doing everything without seeing what he does — and this with his laboratory moving at 300 miles per hour. The printer gets its exposure light from a single bulb which is near the source of contact but which is shielded so that it throws its light down to a reflector before the printing surface. The light which comes back up to the plane of contact is in evenly diffused parallel rays so that there is no chance of unequal light distribution. As soon as the print is made, the paper is placed in a holder similar to that used for the film, and is speeded through the same four processes of de (Continued on Page 144) American Cinematographer March, 1941 113