Final answer:
Optical mixing occurs when the eye mixes two adjacent colors, causing the viewer to perceive a different color between the two.
Step-by-step explanation:
When the eye mixes two adjacent colors, causing the viewer to perceive a different color between the two, this is called optical mixing. Optical mixing occurs because the eye's cone cells, responsible for color vision, have overlapping sensitivity to different wavelengths of light. This can result in the perception of new colors or color effects when two adjacent colors are mixed.
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