Self-recording Glossmeter of Rotating Specimen Type

Abstract

A self-recording glossmeter of rotating specimen type is devised. The angle between the illuminator and receptor axes is set at 90° which is adjustable to any given value from 45° to 180° and the specimen is rotated. The aperture angles are about 21'×°330' (adjustable) for the illuminator, 32'×°30' for the receptor and the illuminating field has the section of 1cm×1cm. Photomultiplier is used in the receptor and a recording mV-meter as the recorder, its sensitivity being 1 mV/cm. The spectral sensitivity of the receptor is approximated to that of the normal eye by using a correcting color filter, while the light source is a 40W tungsten lamp. The sensitivity for recording can be varied at six steps by a potential divider in the output circuit of 931A. At present the ratio of the maximum sensitivity to the minimum is 200 : 1 and at the maximum sensitivity the recorder gives the deflection of about S cm for white matt surfaces under 45°-45° condition of illumination and viewing, Curves recorded for various types of specimens are shown.