Apparatus and method for controlling film density for an apparatus for exposing photographic film with image data
US5021978A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1989 |
| Grant date | Jun 4, 1991 |
| Priority date | — |
| Expiry date | Apr 21, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/4078
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A predetermined gradation of film transmittance levels, e.g. a gray scale, provided by a film exposure system is calibrated so as to consistently create an image on photographic film in accordance with the predetermined gradation of film transmittance levels. A light source is responsive to a drive signal, for generating light so that the exposure of different portions of the film to the light can be varied as a function of the drive signal so as to vary the resulting transmittance level of the portions of the film after the exposed portions of film are developed in order that the image can be formed on the film, and a sensing device senses the transmittance level of a developed portion of film exposed to at least one preselected value of light exposure and generates a transmittance level signal representative of the sensed transmittance level. The drive signal is adjusted as a function of the sensed transmittance level so that the range of transmittance levels produced by exposing the film to the light in response to the adjusted drive signal approximates the predetermined gradation of film transmittance levels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.