Researches in colour vision and the trichromatic theory (1913)
Abney, William de Wiveleslie, Sir, 1843-1920 · London : Longmans, Green · leaf 89
APPARATUS TO ALTER INTENSITY 69 a motor, E. When the sectors are rotated by means of the motor, the apertures can be opened or closed by the lever H at will. The rims of the sectors are graduated in degrees of arc. There have been various attempts made at some time or another to prove that the… … Fig. 22. degrees of aperture. It was not till after exhaustive trials that the writer adopted the sector method for the purpose of assisting in colour measurement. Lights of various colours were reduced by the sectors against a light which could be moved away from a screen to any required distance,…
Color Perception · Color blindness · Color vision
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