Automatic Recording Transmission Reflection Densitometer

Abstract

A photoelectric densitometer which can record automatically characteristic curves of photosensitive materials has been devised. This densitometer can read on constant pitch scale for density reading from 0.0 to 4.0 on transmission or reflection measurement with a set of interference-type narrow band filters which have peak at 435, 546 and 644 m, u respectively, in conformance with ASA. The output signal of photomultiplier has a constant value to changing of the density of specimen by a servo mechanism and a logarithmic attenuator. As a relation between the density of specimen and the position of attenuator is complementary, optical density is possible to record with constant pitch on the Y axis of XY recorder which is built in this densitometer. The circuit elements of this densitometer are all transistors to minimize the instrument.