MotionShine01 / Red and green
The most common
Protan and deutan types make reds and greens hard to tell apart.
Free tool
Color blindness simulator, check your design.
Drop a picture, a screenshot or a design and see it the way people with the main kinds of colour blindness see it: red-blind (protanopia), green-blind (deuteranopia), blue-blind (tritanopia) and no colour vision (achromatopsia), side by side with the original. Turn down the strength for milder forms. It is a simulation to check charts, maps, buttons and brand colours, not an eye test.
Simulation: Machado, Oliveira and Fernandes (2009). Milder forms are approximated with the strength slider.
Simulated in your browser. Your picture is never uploaded.
Design for everyone
Colour should not be the only clue.
02 / Blue and yellow
Rarer
Tritan types confuse blues with greens and yellows with pinks.
03 / Fix
Add a second cue
Labels, patterns, icons or contrast in lightness, so meaning never hangs on hue alone.
Questions
Good to know.
How does the simulator work?
Each pixel's colour is changed with the matrices from Machado, Oliveira and Fernandes (2009), which model how each type of colour vision responds.
Is this a colour blindness test?
No. It shows how a picture may look to others. An eye care professional tests colour vision.
Which type is most common?
Red-green types are the most common, mostly in men; blue-yellow and total colour blindness are rare.
What should I look for?
Things that differ only by colour, such as red and green lines in a chart or a red error state.
Is my picture uploaded?
No.