(under subclass 416) Subject matter wherein more than one filter is provided for the purpose of additively using more than one filter at the same time to produce a desired tint or shade for the purpose of comparing this produced tint or shade with an unknown color, or wherein a plurality of filters are provided, one of which is available at a time, as for the purpose of selecting only one visible band of radiation at a time from the light reflected from or transmitted through the sample.
(1) Note. This sub will take wedge-shaped filters which pass different wavelengths.
SEE OR SEARCH THIS CLASS, SUBCLASS:
43, for optical pyrometers which measure the temperature of a light emissive object by means of filters.
51, for optical tests which use infrared or ultraviolet radiation in the claimed test.
319+, for absorption spectrophotometers which utilize a dispersing member such as a prism or a diffraction grating rather than a filter to produce a plurality of narrow bands of visible radiation before or after radiation is reflected from or transmitted through a substance.
404, for photos:graphic color test devices which may use a plurality of filters additively or sequentially for copying purposes such as color correction, colored negative examination, and colored light meters. However, see the pyrometric subclasses 43+ of this class where the claims or disclosure indicate the light reading to be in terms of temperature.
405, for tristimulus apparatus which utilize three filters, sequentially or simultaneously, corresponding to the stimulus received by the human eye. 406, for apparatus using three or more colored filters, sequentially, which is capable of trichromatic examination of light or material.
SEE OR SEARCH CLASS
348, Television,
655+, for apparatus which may use a plurality of filters to adjust the color balance in color television systems.
351, Optics: Eye Examining, Vision Testing and Correcting,
216+, and 233+ for filters which are selectively interposed in the line of vision.
434, Education and Demonstration,
102, for color comparison charts which utilize filters to show the effect of the addition of various colors on light.
