Color image retrieval from monochrome transparencies

A novel method for recording and retrieving full color images with panchromatic black-and-white film is presented. Color information is retained in the monochrome recording by assigning different spatial carriers to each of the image's tricolor components. Impressing these carriers is accomplished by means of multicolored gratings that have characteristics related to screen plates of the old additive color methods. Encoded color information is preserved and crosstalk is avaoided with the aid of linear photographic storage. To play back color, the recording's Fourier spectrum is first displayed in a partially coherent polychromatic optical system. The Spectrum is then modified by a spatial filter so that orginal color values are restored in the final projected image. This method, a special application of linear multiple image storage, can be extended to four or more spectral zones rather than to the conventional three-color method. Unlike many previous additive color schemes, this method has no registration restrictions and requires only minor camera modifications in order to implement it.