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1952 Theatre Catalog, 10th Edition, Page 293 (257)

1952 Theatre Catalog, 10th Edition
1952 Theatre Catalog
1952 Theatre Catalog, 10th Edition, Page 293
Page 293

1952 Theatre Catalog, 10th Edition, Page 293

FIG. 4C. The visible frame-line mark on raw and processed nitrate film formerly manufactured by Canadian Kodak.

appears black. In white light fiuorescenttreated and untreated films look exactly the same. Extensive tests in both the laboratory and the trade indicate that the fiuorescent treatment of the base has no detrimental effect on the film before or after development.

This simple and effective method of rapidly distinguishing nitrate and safety film in bulk form is illustrated in Figure 5 which shows a composite nitrate and safety film roll on an exchange reel. The nitrate film appears black and the fiuorescent-treated safety film appears white in this reproduction. The contrast between the two films is much more striking in actual practice or in a color photograph where the edge of the safety film appears purple.

A suitable inexpensive ultraviolet lamp in various table, overhead, portable, spot, or fiood-light models may be purchased from several manufacturers complete with transformer and filter ready for use. A 100owatt bulb is recommended for general uSe but smaller or larger ones may be obtained if desired. The ultraViolet bulbs and other parts may also be purchased separately from electrical supply stores and assembled in standard fixtures. Figure 6 illustrates how easily film may be examined by just passing it in front of an ultraviolet lamp of this type.

The ultraviolet lamp should be equipped with a hood or refiector and care should be taken not to expose the eyes for long periods to direct ultraviolet radiation from these lamps. Provided such care is taken, ultraviolet lamps present no personnel hazard. They are in constant use in various other industries, for example, for identifying markings on clothing in laundries.

It should also be pointed out that the above method of examination is intended for processed film only and that if used


FIG. 5. This illustration shows a mixed roll of

fluorescent-treated safety film (white) and un treated nitrate film (dark) on an exchange reel.

(Photographed with an ultra-violet source.) The

oldge of the treated safety film is actually colored

purple and the nitratle lfill-n black in ultra-violet ig t.

in the inspection of raw stock, fogging of the latter will result.

Fluorescent treated film base is now being used for all 35mm Eastman safety motion picture film without exception. This treatment, together with the new frame-line mark, thus assures positive identification of all 35mm Eastman safety film of present manufacture.

Motion picture films manufactured prior to the adoption of the new support identification system described above may sometimes be difficult or impossible to identify directly as nitrate or safety. There are, however, some simple tests which can be used to establish the identity of the base. Information regarding these tests is available upon request.

Uniformity in Manufacture

With its many years of experience in the manufacture of motion picture film, the Eastman Kodak Company quite naturally observes every possible precaution to assure uniformity in the quality of its product. Samples from all coatings are thoroughly tested for their photographic and physical properties and must pass careful scrutiny of trained inspectors.

The matter of accurate slitting and perforating is of the utmost importance and is accomplished only by constant vigilance on the part of experts to keep the slitting and perforating machines at the highest degree of precision.

Motion picture film in the 35mm width is perforated in three different ways. All present black-and-white negative films and all former color films have the Standard Negative type perforation shown in Figure 7A. This perforation (commonly referred to as Bell and Howell) has been used for these purposes because of its excellent registration characteristics. Black-and-white positive hlms have the Standard Positive type perforation shown in Figure 7B. This perforation is used for black-andwhite and more recently for certain color release print films because long experience has shown that it gives greatly increased wearing properties to the film. The third type of perforation, shown in Figure 7C is one originally introduced by DuBray and Howell in 1932, which combines the good registration characteristics of the Standard Negative per FIG. 6. An ultra-violet lamp used for examining a roll of film to determine whether it is on fluorescenttreated safety base. (Photographed with white light.)
1952 Theatre Catalog, 10th Edition, Page 293