Photographic printer with automatic slope compensation
US4149799A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1977 |
| Grant date | Apr 17, 1979 |
| Priority date | — |
| Expiry date | Nov 4, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B27/80
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The photographic printer of the present invention automatically derives and stores slope compensation factors which are used in subsequent printing to compensate for exposure. Reference or slope center values are stored for a reference negative and prints of various negatives are made. A print which requires correction is selected from the test prints which have been made, and the desired density corrections for that print are supplied to the printer. The density values of the negative from which the print was made are measured, and slope compensation factors are derived from the slope center values, the desired density corrections, and the measured density values. Exposures in subsequent printings are compensated based upon these derived slope compensation factors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.