On subjective colour phenomena attending sudden changes of illumination

Abstract

The investigation which forms the subject of this paper originated in an attempt to account satisfactorily for the colour phenomena exhibited by Mr. C. E. Benham’s “Artificial Spectrum Top" which, when it was brought before the public, about two years ago, excited considerable interest. The top consists of a disk of cardboard about 4 1/4 in. (108 cm.) in diameter, mounted upon a spindle. One half of the disk is painted black; upon the white ground of the other half are drawn four successive groups of three black lines, having the form of concentric arcs of 45°, which are at different distances from the centre, as shown in the annexed figure; the thickness of the lines is about 1/25 in.(1 mm.).