Color Blindness Simulator
Upload an image and see it through protanopia, deuteranopia, tritanopia, achromatopsia and blue cone monochromacy, at any severity.
or browse filesdrop an image here or paste
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Upload an image and see it through protanopia, deuteranopia, tritanopia, achromatopsia and blue cone monochromacy, at any severity.
or browse filesdrop an image here or paste
Drop a picture on the page and it turns into what a person with color blindness sees when they look at it. Pick the type from the list - protanopia, deuteranopia, tritanopia, achromatopsia, blue cone monochromacy or one of the milder forms - and the whole image changes at once. It is the quick test for anything that relies on color to carry meaning: a chart whose red and green lines have to be told apart, a map legend, a warning label, a game's team colors, a slide deck, a website screenshot, a product photo with color options. If two things that should look different turn into the same muddy brown here, some of the people you made it for cannot tell them apart either. Used that way it is a colorblind image checker as much as a color blind filter for images: upload, look, and fix before anyone else has to.
Hold the eye button in the corner of the picture (or the B key) to flip back to normal vision for as long as you hold it. Flicking between the two is the fastest way to spot what the simulated view loses.
Protanopia (red-blind): the red-sensitive cones are missing, and a protanope sees with the other two. Reds look dark and brownish, and red, orange, yellow and green collapse toward one family of olive and yellow tones.
Deuteranopia (green-blind): the green-sensitive cones are missing. Red and green become hard to tell apart, but reds keep their brightness - the most common kind of red-green color blindness in its full form.
Tritanopia (blue-blind): the blue-sensitive cones are missing. These three are the dichromatic forms of color vision, with two working cone types instead of three. Blue shifts toward teal, yellow toward pink and light grey, and blue-versus-green and yellow-versus-violet become the confusions.
Protanomaly, deuteranomaly and tritanomaly are the same three with the cones present but shifted, so the colors are weakened rather than lost. Deuteranomaly is by far the most common color vision deficiency there is, around 5% of men.
Achromatopsia (no color): only rods work, and the world is shades of grey. Achromatomaly is the partial form, with some color left.
Blue cone monochromacy: the red and green cones are missing and only the blue cones and rods work. It is close to seeing in grey, but brightness comes from the blue end of the spectrum: blue skies and blue text stay bright while reds and yellows go dark - which is why a blue cone monochromacy simulation looks different from a plain greyscale version.
Color blindness is not on or off. The Severity slider sets how far the vision is from normal, from 10% to 100%, and the name in the list follows it: drag deuteranopia below 100% and it becomes deuteranomaly, drag deuteranomaly all the way up and it becomes deuteranopia, because full-strength deuteranomaly is exactly that. Choosing one of the milder forms from the list starts it at 60%, a typical case. Achromatomaly works the same way against achromatopsia, and blue cone monochromacy can be weakened too.
The simulation is a published physiological model of color vision deficiency (Machado, Oliveira and Fernandes, 2009), which computes how each missing or shifted cone type changes the colors a person can separate, at every severity in steps of a tenth. It is applied in linear light - the image is decoded from the gamma-encoded values a file stores, transformed, and encoded back - which is how the model was built. Many color blind filters apply the same kind of matrix straight to the stored values, and that darkens mid-tones and pulls the hues away from what the model predicts. Achromatopsia uses true luminance, and blue cone monochromacy the sensitivity curve of the blue cones.
No simulation is a person's actual experience: two people with the same diagnosis can see differently, and a screen cannot show everything the eye does. It is a reliable guide for checking whether colors in an image stay distinguishable, which is what accessibility testing needs.
Download the result as PNG, JPG or WebP at the full resolution of your image, copy it to the clipboard, or share it from a phone. The file name says which type it shows, so a set of versions for a report stays sorted. To check contrast in greyscale in a different way, the grayscale converter has several conversion methods; to fix a color that fails the test, the color changer swaps one color in an image for another.
The images people test for color blindness are often unreleased: a dashboard with company figures, a design before launch, a patient-facing leaflet. Everything here runs in your browser - the picture is never uploaded, and the simulated copy is made on your own device.
Deuteranopia or deuteranomaly. Red-green color blindness covers the great majority of color blind people, and the green-weak form alone is well over half of them. If an image works under deuteranopia and protanopia, it works for most color blind viewers; add tritanopia for the rare blue-yellow case.
Yes, it is its own entry in the list. The image goes nearly grey, but with brightness taken from the blue cones, so it looks noticeably different from achromatopsia: blues stay light and reds turn dark.
It sets how strong the deficiency is. At 100% you see the full form (protanopia, deuteranopia, tritanopia, achromatopsia); below that, the milder protanomaly, deuteranomaly, tritanomaly or achromatomaly, and the name in the list changes to match.
No - this shows how an image looks to someone who is color blind; it does not test your own eyes. A color vision test such as the Ishihara plates, done properly with an eye care professional, is how color blindness is diagnosed.
No. The image is read, simulated and saved entirely in your browser, so drafts, private charts and personal photos never leave your device.