🔵 Tritanopia Simulator
See how an image or palette looks with tritanopia, a rare blue-yellow color-vision deficiency, processed entirely on your device.
Choose an image to see the original and simulated versions side by side. It never leaves your device.
Machado, Oliveira & Fernandes (2009) matrices in linear-sRGB. Approximates average CVD perception. 🔒 Images processed on-device, never uploaded.
How the tritanopia simulator works
Each pixel or swatch is linearised and multiplied by the published Machado (2009) tritanopia matrix, then converted back to sRGB, with a severity slider for milder tritanomaly. The transform models the loss of the blue-sensitive (S) cone, which folds the blue, yellow axis together, so blues drift toward green and yellows toward pink/red. Severity at 100% applies the full dichromat matrix; lower values blend original and simulated colours to approximate tritanomaly. Everything runs on a canvas in your browser.
Tritanopia (blue-weak) is rare but affects blues and yellows, the colors many UIs use for links and highlights, so blue/teal or yellow/pink distinctions are the ones to verify.
Frequently asked questions
What is tritanopia?
Tritanopia is a blue-yellow color-vision deficiency where the blue-sensitive (S) cones are absent. Blues and greens, and yellows and pinks, become hard to distinguish. It is much rarer than the red-green types and affects men and women about equally.
What should I check for?
Blue links versus teal, and yellow versus pink or light-green cues. If these collapse, add text or shape cues or widen the lightness gap.
How common is tritanopia?
Very rare, well under 1% of people, but simulating it still catches blue/yellow ambiguities that affect more common conditions and low-light viewing.
Is my image uploaded?
No. It is processed on a canvas in your browser and never sent anywhere.
Can I simulate partial blue-weakness?
Yes, the severity slider approximates tritanomaly by interpolating toward full tritanopia.
How is tritanopia different from red-green color blindness?
It affects the blue-yellow axis rather than red-green, and it is inherited differently. It does not favour men the way protan and deutan types do, so it affects both sexes about equally. It is also far rarer.
What should I look at under tritanopia?
Blue-versus-teal and yellow-versus-pink cues are the danger zones, since those hues can collapse together. Common culprits are blue links next to teal accents and yellow highlights against light-green or pink states, separate them by lightness or add a non-colour cue.
Why is tritanopia inherited differently from red-green types?
The blue (S) cone gene sits on chromosome 7, not the X chromosome, so tritanopia is not sex-linked and affects men and women about equally. The red and green cone genes are on the X chromosome, which is why protanopia and deuteranopia are far more common in men. Tritanopia is also rarer overall, well under 1% of people.
Should I still test tritanopia if it is so rare?
Yes. It is quick and it catches blue/yellow ambiguities that also trouble more common conditions, ageing eyes (the lens yellows with age, dulling blues), and low-light viewing. If your interface leans on blue and yellow for links, highlights or status, a tritanopia pass is worthwhile insurance even though the condition itself is uncommon.