Duplicating

the process of producing motion-picture prints from duplicate negatives. It is used in large-scale manufacturing of prints, as well as to produce prints with a different frame size from the original (for example, making prints on 35-, 16-, or 8-mm film from a 70-mm film).

In two-stage duplication, a positive master print is first made on duplicate-positive film from the negative, and then a duplicate is made from it on duplicate-negative film; the prints are made from the duplicate. In single-stage duplication methods, a duplicate is made directly from the negative on reversible duplicate-negative film, and the prints are made from the duplicate. The duplicate can also be made from a positive print when the film has been taken on reversible film. In this instance the printing is done from the original positive onto duplicate-negative film. In addition to these methods, which are used in producing blackand-white and color copies, for color films a method is used in which color-separated panchromatic masters are made on blackand-white panchromatic duplicate-positive film from a multilayer color negative and printed through red, green, and blue filters. From these masters, printing is carried out in sequence on a multilayer color duplicate-negative film, using green, red, and blue filters, respectively. After photographic processing a color duplicate is produced on the duplicate-negative film, and the prints are made from it.

In the duplicating process the number of intermediate tones between the maximum and minimum darkening (gradation) of the image being copied may be intensified, attenuated, or changed by selection of the film type and the methods of processing. In terms of density, the image in the duplicate should be close to the optimum image in the negative. Color images are balanced for color trueness by filters used during the printing of the masters. The duplicate-negative film is processed up to a gamma of 0.55-0.65, duplicate-positive film, up to 1.60-1.75, and for all-purpose and reversible film, up to 1.0.

During duplication the fidelity of the tones is distorted, small details are lost, and the graininess of the image is increased; in a color image the color is distorted. These defects become stronger the more times the duplicating process is repeated. In addition to the production of prints, duplicating is also used when a filmed event is to be made part of several films, for printing black-and-white films from color originals, and with certain methods of producing special effects.