• Deuteranopia test
• Protanopia test
• Tritanopia test

Test instruction:

1. Click button"Start"
2. Click the button below the small square which color you believe is closes to that of the main pane.
3. Repeat step 2 as many times as you want (more than ten times preferred).
4. Click button "Finish" to see the results.

Older versions of the above tests:

• Deuteranopia test V1.0
• Protanopia test V1.0
• Tritanopia test V1.0

These color vision tests are based on the confusion lines.

• Copunctal points
• Confusion lines
• RGB-limited confusion lines
• Click-to-draw confusion lines
• Technical notes describes the color vision test implementation scheme.

The protanopia (red-blind, missing long-wavelength photopigment) and deuteranopia (green-blind,  missing middle-wavelength photopigment) tests are almost the same because the long (red) wavelength photo-pigment's spectral sensitivity is very close to that of middle (green) wavelength photo-pigment.  In other words, protanopes and deuteranopes will probably test positive on both tests.

Colblindor has a very readable blog explaining this test, especially, from the view of a color deficient person.

The quality of the test is dependent on the quality of the display device (e.g. CRT).  A good Web site for monitor calibration is Accurate Image Manipulation.  

Gamma value 2.2 is most commonly used for CRT's, so it is used for the first version of each color vision test that does not allow display gamma adjustment .  To find out the correct gamma of your display device, please check its documents or do an exercise at AIM.