Unveiling the Materiality of 19th Century's Color Spaces

ABSTRACT Several color theories flourished during the 19th century, marked by experiments on the distinction between color‐light and color‐matter. This study aims to compare the color plates designed to illustrate three of these color theories, namely M.E. Chevreul's chromatic circle (1861), O. Rood's frontispiece (1879), and C. Henry's color circle (1889). These printed plates played a key role in disseminating their respective theory to a broad public. However, the question of their design remains relatively unknown. A non‐invasive multimodal approach was applied, combining visible and near‐infrared reflectance imaging, x‐ray fluorescence, Raman, and mid‐infrared Fourier transform spectroscopies to characterize the materials and printing techniques used to depict the different color theories. It provided new information on the visual appearance of these plates, as well as a deeper understanding of the design of each unique color space and how it relates to their theoretical conceptualization. Analysis of the materials revealed a number of pigments common to all three color spaces, such as red lake pigment, chromate lead, Prussian blue, minium, and vermilion. The use of these pigments and their positioning in the color space illustrate that the choices of the three scientists are guided by the theory they wish to illustrate. Their objectives are not the same: M.E. Chevreul proposed a chromatic circle to illustrate his contrast of simultaneous colors, whereas O. Rood differentiated between a mixture of colored light and a mixture of colored matter. Finally, C. Henry appears as their heir, representing both color‐light and color‐matter on the same circle while following his esthetic rules of color placement.