Color Bars on Film for Setting up Telecines

The optimum values of the terms in the matrix representing electronic masking in telecines depends not only on the absorptions of the dyes in the film being scanned, but also on the inter-image effects present in the film system employed. Inter-image effects are often of a rather complicated nature even if only one film is involved, and if both negative (or camera-positive) and print films are used, then the inter-image effects occurring in both films and any that arise in the printing process must be considered. If, however, the camera film is exposed to a high level and a low level in each of its three layers in all possible combinations, then eight corresponding colors can be generated on the film being scanned; and if the electronic masking is adjusted so that the telecine outputs from these eight colors are also all at the appropriate one of only two levels, then, for those eight colors, allowance will have been made, not only for the absorptions of the film being scanned, but also for inter-image effects occurring in the system. By choosing the two levels of exposure on the camera film so as to correspond to those occupied by a light gray and a dark gray when exposed normally, the masking based on the eight colors can provide a good first approximation to that required in practice.

Print ISSN

0036-1682

Published

1978-02

Content type

Original Research

DOI

10.5594/J17433