Low contrast film
US5674665A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1995 |
| Grant date | Oct 7, 1997 |
| Priority date | — |
| Expiry date | Nov 17, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/29
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A color negative photographic film wherein on the curve of density versus log E for each color sensitive record: (1) a straight line, which connects the point at density Dmin+0.1 and the point at 1.5log E above the exposure required for density Dmin+0.2, has a mathematical slope .ltoreq. 0.50; and (2) the difference in log E is .gtoreq.1.7 between the point 0.9log E above the exposure required for density Dmin+0.2 and the point where the density difference is 0.1 between the curve and the straight line which results from a linear regression of the three density points at exposures 0.3log E, 0.9log E, and 1.5log E above the exposure required for the density Dmin+0.2; and (3) the difference in log E is .gtoreq.1.20 between the exposure needed for density Dmin+0.1 and the point that corresponds to the exposure, in lux-seconds, of 9.2/(Film Speed). The exposure of the foregoing gray card is a typical normal exposure based on the film speed rating (i.e. the film is not overexposed or underexposed).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.