Bezold's 1876 Plate III a, b and c side by side: two red disks, one on a deep crimson ground (Bezold's 'purple') above and one on yellow below; the same disks with the grounds swapped; and the two disks on a plain buff ground.

Concept · Relationships

Simultaneous Contrast

A color seen beside another seems to shift away from it, so two paints can look alike, or far apart, on different grounds.

The eye exaggerates differences at a boundary. On Wilhelm von Bezold's 1876 plates, two different reds look nearly alike on his purple (now faded to crimson) and yellow (left); swap the grounds and they split apart (center); on neutral paper their true difference shows (right). How Chevreul came to it is told on Chevreul and Colors Side by Side, in Module 1.

  • Mask a color with a scrap of gray card to see it apart from its neighbors.
  • Painters judge a mixture on the canvas, beside what will surround it, not on the palette.
  • Knowing the two disks differ does not make them look different, even to a trained eye.

Image: Smithsonian Libraries via Internet Archive · Public domain

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