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1952 Theatre Catalog, 10th Edition, Page 292 (256)

1952 Theatre Catalog, 10th Edition
1952 Theatre Catalog
1952 Theatre Catalog, 10th Edition, Page 292
Page 292

1952 Theatre Catalog, 10th Edition, Page 292

FIG. 4B. The new Eastman frame-line mark on raw and processed safety film.

that two separate identification systems for safety films are necessary. Two such systems are now in effect and are described in the paragraphs below.

'I. Distinctive Visible

Frame-line Printing A scheme has been devised by which

identification of the base can be com- o

bined with visible frameeline printing as shown in Figure 4. Eastman Motion Picture Positive, Sound Recording, and Duplicating films formerly manufactured on nitrate base carried a widthwise

frame-line mark after every fourth perforation printed along the extreme edge of the film as shown in Figure 4A. All Eastman 35mm Motion Picture film of present manufacture, with exception of certain color films,* now carry a lengthwise frame-line mark after every fourth perforation, located not at the extreme edges of the film, but between the perforations, as shown in Fgure 4B. This is the only area on the film which is ordinarily not exposed in printing. This new safety' frame-line mark when used on safety negative film will not print

through on positive film, provided that care is taken to see that printers never expose the area exactly between successive perforations. A more positive identification is thus obtainedswhenever the new safety frame-line mark is found, one can be reasonably certain that the film is on safety base regardless of nitrate frame-lines or nitrate edge printing which may have been printed through from the negative. If the safety frameline printing is not present on a given black-and-white print, the film is either on nitrate base or on safety base made prior to the use of the new frame-line.

Both the nitrate and safety types of visible frame-line printing are applied to the back of black-and-white films by means of black ink instead of by latent image exposure and, therefore, are visible on the raw film as well as on the developed film as illustrated. The ink used will withstand processing solutions and normal handling wear. Even if the film is flashed before development the ink is visible by reflected light, although not by transmitted light.

It should be noted that nitrate film formerly manufactured by Canadian Kodak carried a visible frame-line mark running lengthwise of the film instead of widthwise, as in the case of Eastman nitrate film manufactured in the United States (see Figure 4C). The Canadian Kodak nitrate frame-line mark was located at the extreme edge of the film. It may, therefore, be distinguished from the new Eastman safety frame-line mark located between the perforations. Thus both the direction and the location of the frame-line mark must be checked to establish the identification of the base.

2. Fluorescent Treatment

The new visible frame-line printing is a useful and necessary method for identifying safety film, but it also has its limitations. In a spliced roll, every separate strip would have to be examined to make sure that the entire roll including leader and trailer was safety film. Correct identification of the whole roll is especially important for sorting films going into storage vaults where a small piece of nitrate ifilm might damage other films. It is also important in sorting film for scrap recovery. In such cases, individual examination of every spliced strip would be very laborious and costly. It was felt that some rapid method of determining whether or not a roll of film is all safety is necessary.

The method which has been adopted by the Eastman Kodak Company is to add a very small amount of a fiuorescent chemical to the safety film base used for 35mm motion picture film. When a 35mm roll of film so treated is viewed on edge under a suitable ultraviolet lamp in a partially darkened room a vivid purple fluorescence is visible, whereas untreated film viewed in the same way

'Note: In the case of films having a jet ant!halation backing on the raw stock. it has been necessary in some cases to apply the frame-line mark with colored ink which is removed during processing, and in other instances to use latent image printing, in which case the frameline mark is not visible until the film has been processed. Thus, even though all color films of present manufacture are on safety base. the processed

tilm may or may not contain the new frameline mark.

1952 Theatre Catalog, 10th Edition, Page 292