Paper, 'Measurement of colour produced by contrast' by William de Wiveleslie Abney Abney writes: 'No definite measurements, as far as I am aware, have been made of the change in colour produced by contrast, except in a small work of my own in which results were given in terms of colour mixtures, and earlier by a brief reference in a work by Rood, in which the change produced was endeavoured to be matched by means of rotating disks.' Annotations in pencil and ink. Subject: Optics Received 5 June 1894 / 9 June 1894. Read 21 June 1894. A version of this paper was published in volume 56 of the Proceedings of the Royal Society as 'Measurement of colour produced by contrast'. 1894