Digital Color Management: Encoding Solutions, 2nd Edition

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Photographic Negatives

Although they generally are designed for a different purpose—to be optically printed onto photographic papers and print films—photographic negative films have inherent properties that make them well suited for input to digital color-imaging systems. In particular, they can record (and make available to a scanner) color information from an extremely wide range of exposures. On many photographic negative films, the dynamic range of recorded exposures can easily exceed a ratio of 10 000:1 (a 4.0 log exposure range).

Dynamic range is one reason why color negative films remain a dominant image-capture medium for professional motion pictures. Their continued use in that application is one reason why understanding their imaging properties is still relevant. There are other reasons as well. For one, there is a legacy of negative images that will need to be digitized and stored, and doing this properly requires an understanding of the unique properties of these media. In addition, negative films represent a class of images that can be considered intermediary, i.e., their image values do not directly represent either the colorimetry of the photographed scene or the colorimetry of the image that ultimately will be produced for viewing. This is an important concept that, as will be shown later, applies to other forms of images and must be considered in the design of any comprehensive imaging system or color-encoding method.

Negative films are low in photographic ...