Color Blindness Simulator: Photo, Video and Live Camera
See a photo, a video file or your phone camera, live, the way people with protanopia, deuteranopia, tritanopia and other color vision deficiencies see it, approximately. Not only still images: a video plays with the simulation on every frame, and the camera shows it as you point the phone. Drag the line to compare with the original. Everything runs on your device: nothing is uploaded.
An approximate simulation, not a test. Real color vision varies from person to person, and a phone camera and screen add their own color shifts.
What colors look like to color-blind people
| Color | Protanopia | Deuteranopia | Tritanopia | Achromatopsia |
|---|---|---|---|---|
| Red | #5E5E0D | #939300 | #FF004E | #7F7F7F |
| Orange | #B2B208 | #C5C500 | #FF98A5 | #B8B8B8 |
| Yellow | #FFFF00 | #FFFF00 | #FFEEF1 | #F7F7F7 |
| Green | #797900 | #6D6D0F | #397487 | #6D6D6D |
| Lime | #F2F200 | #DBDB29 | #79E9FF | #DCDCDC |
| Blue | #0000FF | #0000FF | #006288 | #4C4C4C |
| Purple | #2B2B80 | #47477F | #782F3A | #464646 |
| Pink | #C8C8CB | #D5D5C9 | #FFC1C7 | #D0D0D0 |
| Brown | #47472B | #646421 | #A6253F | #585858 |
Of the 9,275 pairs of CSS named colors that look clearly different to typical vision (ΔE 10 or more), this simulator merges (ΔE below 3) 47 for protanopia, 37 for deuteranopia, 85 for tritanopia. For protanopia that includes darkgreen #006400 and red #FF0000. The guide how color-blind people see, and how far to trust a simulator compares this model with two others on the same colors.
Types of color vision deficiency
- Protanopia: no working red-sensitive (L) cones. Reds look dark and brownish and are easily confused with greens.
- Deuteranopia: no working green-sensitive (M) cones. Reds and greens fall into the same range of yellows and browns.
- Tritanopia: no working blue-sensitive (S) cones. Blue and green, and yellow and pink, become hard to tell apart. Rare.
- Protanomaly and deuteranomaly: the red or green cones are present but shifted. The effect ranges from barely noticeable to as strong as the -anopia, which is what the severity slider shows. Even at full severity the slider is a different model (Machado 2009) from the -anopia views (Viénot 1999), so the colors do not match: across 4,096 test colors they differ by ΔE 6.2 on average for protan and 5.0 for deutan, up to about 15. Deuteranomaly is the most common form of color blindness.
- Tritanomaly: weakened blue sensitivity. Rare.
- Achromatopsia: no working cones in its complete form, so no color. It is very rare and also brings low sharpness and strong sensitivity to light, which a color filter cannot show.
How the simulation works
Each pixel is converted from sRGB to linear light, multiplied by a matrix that removes or weakens one type of cone response, and converted back. Protanopia and deuteranopia use Viénot, Brettel and Mollon (1999); tritanopia uses the two-plane model of Brettel, Viénot and Mollon (1997), because the single-plane model is wrong for it; protanomaly and deuteranomaly use the severity matrices of Machado, Oliveira and Fernandes (2009); tritanomaly blends the tritanopia result with the original; achromatopsia keeps only luminance (Rec. 709 weights in linear light), which approximates cone monochromacy — rod monochromats, who see with rods only, also perceive brightness differently. The matrices for Viénot and Brettel come from the public-domain libDaltonLens. Many simulators skip the linear-light step, which makes reds and purples look far too dark.
Your photos and camera stay on your device
Photos, videos and every camera frame are processed in your browser, on the graphics chip where WebGL is available. Nothing is uploaded or stored, and the camera is released as soon as you leave the page or switch tabs. The camera starts only when you press the button.
Color blindness simulator: questions
- What does a color blindness simulator do?
- It recolors an image so that a person with typical color vision can see, approximately, which colors a person with a color vision deficiency can and cannot tell apart. Designers use it to check charts, maps, interfaces and print before they ship.
- How accurate is the simulation?
- It follows published models: Viénot, Brettel and Mollon (1999) for protanopia and deuteranopia, Brettel, Viénot and Mollon (1997) for tritanopia, Machado, Oliveira and Fernandes (2009) for protanomaly and deuteranomaly, and for tritanomaly a blend of the tritanopia result with the original, all computed in linear RGB. It is still an approximation: color vision differs from person to person, and screens, cameras and lighting shift colors too. For example, pure red #FF0000 comes out as #939300 for deuteranopia and green #008000 as #6D6D0F.
- What is the most common type of color blindness?
- Red-green deficiencies are by far the most common, and among them green weakness (deuteranomaly) is the most frequent. About 1 in 12 men and 1 in 200 women of Northern European ancestry have some red-green deficiency; it is less common in other populations. Blue-yellow (tritan) deficiencies and complete color blindness are rare.
- Can I use my phone camera?
- Yes. Tap «Use camera» and allow camera access; the rear camera opens by default and «Switch camera» flips to the front one. «Full screen» fills the phone screen with the picture, the type buttons and a handle to drag between the original and the simulation. Freeze a frame and save it. The video is processed on your phone and never leaves it. The camera needs WebGL, which almost every current phone browser supports.
- Can I simulate color blindness on a video?
- Yes. Choose «Photo or video» and pick a video file: it plays on a loop, without sound, with the simulation applied to every frame, and you can pause, scrub, change the type and save the current frame. The file is played by your browser and never uploaded. Which formats work depends on the browser; MP4 (H.264) and WebM play almost everywhere.
- How can I see an image the way a color-blind person sees it?
- Press «Photo or video» on this page and pick the image or a video file, then choose a type: deuteranopia and deuteranomaly, the green-weak types, are the most common. Drag the line across the picture to compare the simulation with the original. On a phone, «Use camera» shows the live view instead. The picture is processed on your device and never uploaded.
- Which colors look the same to color-blind people?
- Of the 9,275 pairs of CSS named colors that look clearly different to typical vision (ΔE 10 or more), this simulator merges (ΔE below 3) 47 for protanopia, 37 for deuteranopia, 85 for tritanopia. The most striking: darkgreen #006400 and red #FF0000 for protanopia; firebrick #B22222 and green #008000 for deuteranopia; mediumpurple #9370DB and olivedrab #6B8E23 for tritanopia. Red-green types confuse reds, greens, browns and oranges; tritanopia confuses blues with greens and yellows with pinks and violets.
- Is this a color blindness test?
- No. A simulator shows how colors may look; it cannot tell whether you are color blind. Only an eye-care professional can diagnose a color vision deficiency.
- How do I make a design work for color-blind people?
- Do not rely on color alone: add labels, patterns, icons or shapes, as WCAG success criterion 1.4.1 (Use of Color) asks. Keep enough lightness difference between colors that must be told apart, check text with a contrast checker, and look at the result in this simulator for protanopia, deuteranopia and tritanopia.
Sources
- Viénot F., Brettel H., Mollon J. D. (1999). Digital video colourmaps for checking the legibility of displays by dichromats. Color Research & Application 24(4), 243–252. DOI
- Brettel H., Viénot F., Mollon J. D. (1997). Computerized simulation of color appearance for dichromats. Journal of the Optical Society of America A 14(10), 2647–2655. DOI
- Machado G. M., Oliveira M. M., Fernandes L. A. F. (2009). A physiologically-based model for simulation of color vision deficiency. IEEE Transactions on Visualization and Computer Graphics 15(6), 1291–1298. DOI
- libDaltonLens: public-domain implementation of the Viénot and Brettel models (DaltonLens). Link
This simulator is for checking designs and is not a medical device or a diagnostic test. If you think you have a color vision deficiency, see an eye-care professional.