(under subclass 416) Subject matter wherein there are rotating sequential filters positioned in the light path to rotate during the test.
SEE OR SEARCH THIS CLASS, SUBCLASS:
217, for modulating photometers for the examination of the intensity of light.
434, for light transmission tests of the sequential type which may involve mechanical, electrical, or electro-optical modulating means, and where only the intensity of the light transmitted through a substance is involved.
447, for light reflection tests which include modulation of the reflected light from a substance where only the intensity of the reflected light is involved.
