David Novick's Color Illusion Page: "Impossible" Munker Illusions

This page explores Munker illusions and creating the most salient effects.

Desaturating the central colors helps increase the effect of the context colors. The central rectangles seem green and orange, but they are exactly the same color.
Another Munker Illusion, trying to get maximum color difference. Again, desaturating the central colors helps increase the effect of the context colors. The central ovals seem blue and violet, but they are exactly the same color.
The clearest Munker illusion come from the biggest differences in foreground colors. Can noticeable effects come from much smaller differences? Here's a first example, with blue/violet foreground colors leading to greenish and orangeish illusory colors.
And here's a second example, where orange/red foreground colors lead to greenish and blueish illusory colors. Although these aren't as strong as other examples of the Munker illusion, the effects are still quite noticeable.
I thought the biggest effects would come from target colors from areas on the color wheel with the greatest apparent change in hue. For example, here's foreground blue/green with background orange.
With the same blue/green foreground colors, here the illusion with the target colors squarely in the middle of the broader area of yellow in the color wheel. There's still a perceptible illusory difference.
Moving the other direction around the color wheel, here are the same blue/green foreground colors with target color from the broadest area of red on the color wheel. There's still a fairly obvious color-difference illusion.
And where the color wheel changes from red to violet, there's again a difference in the illusory colors. But these differences seem fairly constant, reflecting the difference between blue and green rather than the gradient of the apparent color change around the wheel.
The effect of the size of the difference of the foreground colors of the Munker illusion can be seen from comparing close and distant foreground colors using the same target color. With orange target color, green/violet produces stronger illusion than green/blue.
And with yellow target color, the relatively weak illusion with green/blue becomes much more vivid with green/violet. Modulo the target matching one of the foreground colors, the impact of the illusion appears to be a function of the differences between the foreground colors.
Here's another exploration of Munker illusions, this time when the target color is close to the foreground color. To start, here are cases when the targets are white (really a color completion illusion) and as far from the foreground colors as possible, giving good illusions.
When the target color is exactly the same as one of the foreground colors, one of the targets disappears. But when the target has the same hue with lower saturation, there are clearly visible differences.
Here's the same idea with green/violet foreground colors. As base cases, here are targets that are white and then a color as opposite of the foreground colors as possible. Both produce strong illusions.
Likewise, when the target color is exactly the same as one of the foreground colors, one of the targets disappears. But when the target has the same hue with lower saturation, there are again clearly visible differences.

Return to David's color illusions page.
Return to David Novick's home page

Department of Engineering Education and Leadership | The University of Texas at El Paso

May 18, 2018