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Ragona-Scina's (1847) Method for, and Observations of, Simultaneous Color Contrast

O'Shea, R. P., Brini, S. & Wade, N. J. (2016). Ragona-Scina's (1847) Method for, and Observations of, Simultaneous Color Contrast. i-Perception, 7(2), doi: 10.1177/2041669516643239


In 1847, Domenico Ragona-Scinà (1820–1892) published a method of optically superimposing images using an angled piece of colored glass. He showed that if one looks at a black, filled circle through the colored glass and superimposes on it the reflection from the glass of something white, the filled circle looks tinted with the complementary color of the background: simultaneous color contrast or contrast color. Although Ragona-Scinà’s method and his observation have been cited into the 21st century, the former for its simplicity and the latter for its challenges to early theories of color vision, some errors have crept in and the phenomenon still lacks an agreed-on explanation. We provide some biographical information about Ragona-Scinà, set the method and the observation into their historical and theoretical contexts, and give a translation into English of Ragona-Scinà’s Italian-language paper.

Publication Type: Article
Additional Information: © The Author(s) 2016. This article is distributed under the terms of the Creative Commons Attribution 3.0 License ( which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (
Publisher Keywords: Color perception; simultaneous color contrast; optical superimposition; multi-field tachistoscope; methods for research in visual perception; Ragona; history
Subjects: R Medicine > RE Ophthalmology
Departments: School of Health & Psychological Sciences > Healthcare Services Research & Management
Text - Published Version
Available under License Creative Commons: Attribution 3.0.

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