A Scanner for Making Photographic Masks.

Details:

Year: 1959
Pages: 10

Summary:

The scanner described is a research instrument which makes color-correcting masks from a set of three separation negatives. It was designed to improve present masking methods, and to investigate new ones. For these purposes, it possesses many advantages over other scanners, and over purely manual methods. The three negatives are revolved around a fluorescent tube, and the electric signals thus generated are logged to produce three voltages that are proportional to the density. These signals are operated upon by relatively simple analog-computer circuits to produce any of a large variety of masks. The resulting signal, representing the density of a specific mask, is effectively antilogged by an amplifier, glowlamp, and film combination as it is exposed on the end of the same cylinder which holds the negatives. Since it does not carry picture detail, this machine can be much less complicated than scanners which do, and since it scans negatives rather than transparencies, it does not need to cover as large a density range. Besides improving present masking techniques and devising new ones, this instrument can perform some jobs which are otherwise complicated, such as selective or area-masking and 100 percent under-color removal.