Colour measurement and mixture. Published under the direction of the Committee of General Literature and Education appointed by the Society for Promoting Christian Knowledge (1891)
Abney, William de Wiveleslie, Sir, 1843-1920, Society for Promoting Christian Knowledge (Great Britain). General Literature Committee · London: Society for promoting Christian knowledge; New York, E. & J. B. Young & co. · leaf 49
, which moves a sleeve inwhich is fixed a pin working in a screw groove,which allows the aperture in the sectors to beopened and closed at pleasure during their revo-lution ; D is an electro-motor causing the sectors 46 COLOUR MEASUREMENT AND MIXTURE. to rotate. To show its efficiency, if two… … Fig. 7. — Rotating Sectors. and the rotating sectors are interposed in the pathof the light illuminating the shadow cast on thewhite strip, the aperture of the sectors can beclosed till the white paper appears absolutelyblacker than the black paper. White thus be-comes darker than lamp-black, owing…
Color
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