The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 25, 1980
Filed:
Feb. 22, 1977
Michael P Bey, Temple Hills, MD (US);
Paul P Bey, Temple Hills, MD (US);
Other;
Abstract
A photometric device for measuring and displaying by digital means primary color densities of a color negative to be printed to determine densities of color compensating filters. Exposure time, including reciprocity effect compensation for the photographic paper, is displayed digitally and determined by density measurements of the projected image. A reference area of a color negative illuminated by light through color compensating filters is projected on the aperture of a probe which directs light through a light guide to a photodetector. The resulting photocurrents generate voltages amplified by a first and second variable gain linear amplifier. The second amplifier provides primary color and exposure density reference by means of gains stored by measurement of a standard negative. Digital display means is provided to display memory gains for accurately modifying or resetting reference gains. The output of the second amplifier is coupled to a signal integrator alternately gated by a pulse generator and an exposure-time controlled integrator. A voltage comparator and digital circuitry coupled to the signal integrator serve to display the density of color compensation negative optical density representative of a particular print reflectivity. The exposure-time integrator is coupled to a voltage comparator which gates digital counters to display exposure time including compensation for reciprocity effects. An alternative exposure-time circuit utilizes analog means to display exposure time.