I think I may have found the reason in the Maxwell's Spot PDF the article links to. It says: "The reason why this illusion [Maxwell's Spot] does not tend to be

I think I may have found the reason in the Maxwell's Spot PDF the article links to. It says: "The reason why this illusion [Maxwell's Spot] does not tend to be clearly visible with LCDs may be because the peak wavelength of blue in LCDs is on the shorter wavelength side than 460nm." I don't know what technology my monitor is using, but it's possible it's LCD. Or maybe OLEDs have a similar color shift.