Reflection densitometer for light sensitive paper - uses several independent receivers to avoid stray light

摘要

A remission densitometer for measuring optical density, in partic. of light sensitive paper, has an optical illumination system forming a strip light spot on a test strip of the paper with approximately perpendicular incidence angle. It also contains a light receiver system picking up some of the light reflected from the strip at less than 45 degrees and an optoelectrical transducer. It is designed for exact retention of the standard illumination conditions avoidance of the picking up of stray light, and convenient readjustment. The receiver system has several independent parts positioned rotation symmetrically around the spot at specific azimuth angles with mirrors and lenses delivering the reflected light to the transducer.