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

Robert P O'Shea,Stefano Brini,Nicholas J Wade

doi:10.1177/2041669516643239

Robert P O'Shea, Stefano Brini + Show 1 more

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https://doi.org/10.1177/2041669516643239

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Abstract

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.

Highlights

Ragona-Scina (1847b) showed that if one looks at a black, filled circle through a colored piece of glass, and optically superimposes white light on it, by reflection from the front surface of the glass, the filled circle looks tinted with the complementary color of the glass, a phenomenon known as simultaneous color contrast (e.g., Ekroll & Faul, 2013) or contrast color (e.g., Whittle, 2003)
Ragona-Scina ’s observation challenged early theories of color vision and his method for producing it was new for most vision researchers
We give some biographical information about Ragona-Scina, set the paper into its historical and theoretical context, and provide a translation of RagonaScina ’s (1847) paper into English

Summary

Introduction

Ragona-Scina (1847b) showed that if one looks at a black, filled circle through a colored piece of glass, and optically superimposes white light on it, by reflection from the front surface of the glass, the filled circle looks tinted with the complementary color of the glass, a phenomenon known as simultaneous color contrast (e.g., Ekroll & Faul, 2013) or contrast color (e.g., Whittle, 2003). Ragona-Scina ’s (1847b) method was to look through a colored sheet of glass tilted about 45 to a horizontal line of sight at a black, filled circle drawn on a vertical white sheet of paper while at the same time seeing the reflection, from the front surface of the glass, of a similar horizontal white sheet of paper with its own black, filled circle.

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