Colori

Color Vision Science

Where does your color world end?

Every person's color perception is subtly different — and the boundaries of what you can distinguish shift across the color spectrum. Near yellow, your eye is extraordinarily precise. In the purple-blue range, the threshold is much larger.

In 1942, David MacAdam showed that around any given color there exists an ellipse of colors you cannot distinguish from it. Colori extends this classical work into the full three-dimensional color space, probing 35 locations across the visible gamut.

Every game you play generates real psychophysical data — thresholds, reaction times, and discrimination sensitivity along three cardinal axes: red–green, blue–yellow, and black–white. With enough players, the picture becomes a map.

reference colors probed per game, on a BCC lattice in RGB space

directions of color change around each reference color

difficulty levels, from barely visible to obvious

threshold ellipsoids per player, one per reference color, fitted from your games

Gameplay

Simple to play.
Deep in science.

Each round lasts seconds. Over 35 rounds you cover the full RGB color cube, generating a personal map of your color discrimination ability.

STEP 01

🎨

Find the odd discs

A reference color is shown. A field of discs appears — most match the reference, but some are slightly different. Tap every disc that looks different.

STEP 02

⚡

Speed and precision

Subtle differences earn more points. Tap quickly during the green phase for double points. Each error costs a life — precision matters as much as speed.

STEP 03

📊

See your sensitivity

After every 7 rounds, a summary shows how many targets you found along red–green, blue–yellow, and light–dark. After the game, see how you compare with everyone who has played, and open ✨ My Color for your own color space.

Your Results

What your numbers mean

EVERY 7 ROUNDS

🎯

Found per color axis

The share of differing discs you found along red–green, blue–yellow, and light–dark: your own hit rate, not a comparison with others.

AFTER THE GAME

🏅

Rank and profile

Your score's rank among all games played. With sharing on and past round 21, also your ColoriQ, red–green, blue–yellow, light–dark, accuracy, and speed, each compared with all players.

✨ MY COLOR

🫧

Your ellipsoids

Your personal color space: 35 threshold ellipsoids to rotate in 3-D and compare with the average player. Yours after 3 shared games.

See the average player

How your profile is computed

Every disc is a trial: found or not. Each night we fit one threshold ellipsoid per reference color to all games of all players. Your ellipsoids are this population field, stretched along red–green, blue–yellow, and light–dark by your own data. The more you play, the more they are yours.

Your ColoriQ summarizes your overall threshold. Like an IQ score, it is normed on all players to a mean of 100 and a standard deviation of 15.

Colori is a game and a research tool, not a clinical test. Results depend on your screen and lighting, and cannot diagnose a color vision deficiency.

Peer-Reviewed Research

The science behind the ellipsoids

In our lab study, eight observers mapped the three-dimensional structure of color space by measuring discrimination ellipsoids — regions of colors around a reference that cannot be told apart from it — at 35 locations arranged on a body-centered cubic lattice within the RGB cube.

The rotating visualization you see on this page places one ellipsoid at each of those 35 locations. Their colors are the actual reference colors; their sizes reflect how large the discrimination region is at each point. Near neutral grays, the ellipsoids are larger. Near saturated primaries, they are smaller and more elongated.

This work extends the classical 2D discrimination ellipses of MacAdam and Wyszecki & Fielder into a complete empirical 3D metric field across the full color gamut. Colori uses the same 35 reference colors. The lab study measured a few observers very precisely. Colori measures many players more coarsely and combines them, so we can see how color spaces differ between people.

Red–Green

From reddish to greenish.

Blue–Yellow

From bluish to yellowish.

Light–Dark

From darker to lighter.

Journal of Vision · Open Access

An empirical three-dimensional metric field for color space

Jan Koenderink, Andrea van Doorn, Doris I. Braun & Karl R. Gegenfurtner

Journal of Vision 26(9):3 · 2026 · doi:10.1167/jov.26.9.3

Eight observers measured discrimination regions at 35 reference colors on a body-centered cubic lattice in the RGB cube, probing seven orientations (14 directions) around each. Minimum-volume ellipsoids fitted to these regions form a metric field that is spatially smooth and, up to an individual scale factor, consistent across observers. The grain grows along the achromatic axis. Compared with CIEDE2000, the overall variation in scale agrees broadly, but the local anisotropy differs.

Read the article

Research Group

Built at a world-leading vision lab

Colori is developed by the Allgemeine Psychologie group at Justus-Liebig-Universität Gießen — one of Europe's leading centers for visual psychophysics and color science.

Justus-Liebig-Universität Gießen

Abteilung Allgemeine Psychologie
Prof. Dr. Karl R. Gegenfurtner

This project was supported by European Research Council ERC AdG Color 3.0 (884116), by DFG Sonderforschungsbereich SFB/TRR 135 (222641018), and by DFG Excellence Cluster EXC 3066/1 “The Adaptive Mind” (533717223).

ERC Advanced Grant Color 3.0

DFG SFB/TRR 135 Cardinal Mechanisms of Perception

DFG Excellence Cluster EXC 3066/1 The Adaptive Mind

Ethics approval LEK-2026-0039. Data are collected with participant consent for scientific research purposes.