The light intensity of the projector is then adjusted to the required 

 meter reading as indicated hy the photoelectric cells. These three 

 cells are located in front of the slide and grid screen just out of 

 range of the camera . The photograph is taken when the operator presses 

 the camera shutter control button located in the top of' the lever 

 handle, A check on the possible changes of strength, or aging, of the 

 photoelectric cells is maintained by photographing a neutral density 

 filter at a knovn light setting. This is then Inspected in a densio- 

 meter after the film is developed. A neutral density filter is photo- 

 graphed at the beginning and end of each reel of film. It is mounted 

 In a frame similar to that used for the BT grid and is inserted into 

 the grid stage for photographing. 



Before photographing a cruise, a slide is shot -which shows 

 the cruise number. Another slide is shot which indicates the number 

 of prints to be made of each bathythermogram. Thus, the operator of 

 the high speed printer is informed of the beginning and ending of each 

 cruise and the varying number of prints to make as he advances the film 

 through the printer. The cruise number provides a quick reference -vAien 

 Inspecting film in a reader. 



k. Editing and Screening the Film 



After the film has been developed, it is inspected, frame by 

 frame, in a Recordak Microfilm reader (fig. 5). Any errors that may 

 have occurred in the photographing are marked during this inspection 

 and cut out of the film. The film is then spliced and is ready for 

 printing. 



5. Processing the Bathythermogram Prints 



The bathythermograms are made on an enlarging strip paper 

 printer called a Pakomatic printer (fig. 6). This high speed printer 

 uses roll paper in lengths up to 1,000 feet. The paper used for bathy- 

 thermograms is a low contrast, semimatte type known as Resisto-Rapid. 

 It is cut in 500-foot lengths, k^ inches wide. Because of the devel- 

 oping process now being used, it is only slightly heavier than single 

 weight paper. It has a plastic backing to reduce absorption of water 

 during the developing. 



The Pakomatic printer is located in the darkroom adjacent 

 to the developer. The paper is loaded into a large drum or magazine. 

 The magazine is mounted on the upper left hand part of the printer and 

 the paper is threaded over a series of rollers which holds it in the 

 proper position on the paper carriage for making the exposures. It is 

 then threaded around another roller and onto a windup reel. Exposure 

 is automatically controlled by a photocell, with provisions for modi- 

 fication of the photocell readings according to the operator's judge- 

 ment. (Pako Corp., 1955). As each exposure is made, a small knife 

 makes a half inch cut in the paper at the center of the strip midway 

 between consecutive prints. These cuts are three Inches apart. Thej 



