Logvinenko AD, Hutchinson SJ. Evidence for the existence of colour mechanisms producing unique hues as derived from a colour illusion based on spatio-chromatic interactions.
Vision Res 2007;
47:1315-34. [PMID:
17408717 DOI:
10.1016/j.visres.2006.10.025]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Revised: 10/13/2006] [Accepted: 10/18/2006] [Indexed: 11/20/2022]
Abstract
When its spatial frequency is high enough, a grid of grey horizontal strips presented on a coloured background may change its neutral colour. It was found that some background colours induce a strong illusion and some no illusion at all. The effect of the background colour on the illusion was studied for the spatial frequencies of 0.5, 2.5, 4, and 8 c/deg. Thirty chromaticities (evenly distributed across the colour gamut triangle) of the backgrounds in the equiluminant plane, and 24 in the ML plane (where S-contrast was zero), were tested. Five matches were made for each frequency and each background chromaticity. Viewing was binocular. For the low (0.5 c/deg) frequency strips, the backgrounds were found to induce the colour, if any, approximately complimentary to that of the background (i.e., chromatic simultaneous contrast). For the high (8 c/deg) frequency, most backgrounds induced only illusory colours close to unique hues (yellow, blue, and green), with a few backgrounds inducing a mixture of green with blue. Then, the method of adjustment was used to determine the unique hues for the same three observers. A remarkable similarity was found between unique hues and illusory loci, suggesting that the illusion is due to a difference in the spatial resolution of the post-receptor channels producing the unique hues.
Collapse