Figure 3.11.2 from Stockman, A., & Brainard, D. H. (2009). Color vision mechanisms. In M. Bass, C. DeCusatis, J. Enoch, V. Lakshminarayanan, G. Li, C. Macdonald, V. Mahajan & E. van Stryland (Eds.), The Optical Society of America Handbook of Optics, 3rd edition, Volume III: Vision and Vision Optics. New York: McGraw Hill.
Hering's opponent-colors diagram. A diagrammatic representation of opponent colors theory. The upper ring shows a range of colors changing in small steps from green at the top clockwise to blue, red, yellow and back to green. The lower ring shows the hypothetical contributions of each of the color-opponent pairs (red [R] vs. green [G], and blue [B] vs. yellow [Y]) to the appearance of the corresponding colors in upper ring. In accordance with opponent-colors theory, the opposed pairs of colors are mutually exclusive (see text for details). Redrawn from Plate 1 of Hering’s book (Hering, 1920).
Hering, E. (1920). Grundzüge der Lehre vom Lichtsinn. Springer: Berlin.