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Nonlinear Filter

IP.com Disclosure Number: IPCOM000095368D
Original Publication Date: 1965-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Zweig, HJ: AUTHOR

Abstract

A photographic material consisting of photo-bleachable dye, such as a diazo compound, is a non-linear filter. It can be used to enhance the contrast of a print from a low contrast original by placing it between the original and the print. The amount of light emerging from the reverse surface of the filter is initially negligible. It does not become appreciable until the photo-bleachable dye is bleached substantially through its thickness. At this point, the input and output exposure of the filter are essentially equal. In other words, the molecular bottom layer of the filter has a much higher gamma than the top molecular layer on which the light is incident.

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Nonlinear Filter

A photographic material consisting of photo-bleachable dye, such as a diazo compound, is a non-linear filter. It can be used to enhance the contrast of a print from a low contrast original by placing it between the original and the print. The amount of light emerging from the reverse surface of the filter is initially negligible. It does not become appreciable until the photo-bleachable dye is bleached substantially through its thickness.

At this point, the input and output exposure of the filter are essentially equal. In other words, the molecular bottom layer of the filter has a much higher gamma than the top molecular layer on which the light is incident. Thus, with the bottom layer of the filter being adjacent the print, the gamma of the print, in effect, is increased and the densities of the original are reproduced with greater contrast.

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