Complementary Colors: The Illusion

While working in the garage the other day, I found myself staring at my yellow miter saw for a while as I considered a cut I was about to make. When I turned away, I saw a splotch of blue imposed on my gray truck. The blue was an illusion—another interesting feature of complementary colors.

The “sciencey” explanation goes something like this: when you focus on a color like yellow for an extended period, your eyes’ photoreceptor cells (the cones) become overstimulated. These cones are specialized for detecting different wavelengths of light—red, green, and blue—and work together to help you perceive a full spectrum of colors. Staring at yellow, which is a mix of red and green light, can fatigue the red and green cones in your eyes.

When you finally look away at something neutral, like a white wall, all wavelengths of light are reflected back at your eyes. However, because your red and green cones are still recovering from their "workout," the blue cones, which weren’t as active, take over. This imbalance creates the sensation of seeing blue—the complementary color to yellow.

—Mitchell Hegman