Photometer Bench

a laboratory device for determining photometric quantities. Light sources, photometric heads, and various apparatus used in photometry may be installed on a photometer bench and moved over a precisely measured length. The heart of a photometer bench is a pair of rails with a scale (usually 3–5 m in length with 1-mm scale divisions); the instruments and attachments are mounted on carriages, which easily move along the rails. Scattered and undesirable extraneous light is excluded by transverse light-absorbing screens; those positioned at the ends of the bench are solid, and the intermediate screens are equipped with holes to allow passage of the light beam being measured. The auxiliary equipment of a photometer bench includes a plumb line, a distance meter, a rotating light absorber, and a holder with a rotatable limb.