New colors without shooting lasers into your eyes

Effect on different kinds of color vision

• Several red–green colorblind and deuteranomalous commenters report that the illusion works, often producing a vivid blue‑green or lighter green halo, though likely different from “normal” trichromats.
• Others with color weakness see only a pale halo or no “new” color at all; one suggests heavy cone overlap might blunt the effect.
• Some speculate it should work for anomalous trichromats but likely fails for true dichromats (protanopia/deuteranopia). One suggests it might even be used as a diagnostic test, though that’s unproven.
• There is disagreement over some physiological claims in the article about how deuteranomaly works.

How the illusion works and how to view it

• Many clarifications: the black bar is just a countdown; the effect comes from saturating cones via prolonged fixation on the central dot and then watching the shrinking circle/afterimage.
• Moving eyes or blinking reduces the effect; some users “refresh” the countdown or change viewing distance to intensify it.
• Some see nothing, question whether it truly goes “outside” the natural color gamut, or argue it’s just a standard negative afterimage, not a fundamentally new color.

Subjective experiences and comparisons

• Many report a striking, “magical,” ultra-saturated teal/green/cyan halo, sometimes grainy or “TV snow”-like, sometimes reminiscent of psychedelic “ultragreen” experiences.
• Others see different hues (yellowish, orange, purple) depending on custom color combinations, lighting, display settings, or even contact lenses.
• Comparisons are made to Shepard tones (endless pitch illusion), op art, James Turrell installations, and high-contrast typography causing persistent afterimages.

Color vision biology and evolution

• Extended discussion on overlapping cone sensitivities, gene duplication on the X chromosome, and differences between Old World and New World primate color vision.
• Mention of rare human tetrachromacy, bird tetrachromacy, and the challenge of describing a four-dimensional color experience.

Plants, spectrum, and environment

• Side thread on why plants are green, chlorophyll absorption bands, solar spectrum peaks, and hypotheses about energy variance, noise reduction, and historical evolutionary contingencies.
• Another tangent: water’s transmission window defines “visible light,” plus how atmospheric filtering shapes both photosynthesis and visual systems.