Method and apparatus for making color prints
US4192605A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1978 |
| Grant date | Mar 11, 1980 |
| Priority date | — |
| Expiry date | May 8, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B27/735
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Color prints from transparencies which constitute frames or sections of universal film are made on printing paper by ascertaining the quotient or difference of integrated transmittance of the transparencies in green and red light, comparing the signal which denotes such ratio with a variable reference signal whereby the resulting comparison signal denotes the color temperature of light by which the respective transparency was exposed, and carrying out color corrections to depart from correction to neutral gray in dependency upon whether the ascertained color temperature denotes exposure in daylight or artificial light. The value of the reference signal is changed in such a way that the intensity of the ratio-designating signal which is necessary for generation of a comparison signal denoting the switchover point between the classification of transparencies into those respectively exposed by daylight and artificial light is lowered when the overall density of the transparency is lower and vice versa.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.