This simulation model is based on how various forms of CVD perceive each of the independent tristimulus primaries of an sRGB monitor in terms of their luminance function, and then combining certain primaries using coefficients that are modified relative to the type of CVD being modeled.

For instance, protanopia sees the RED sRGB primary as a little less than half the luminance of a normal observer. Thus this protanopia simulator reduces the standard 21% red coefficient to 9.5%, and then combines & scales the red and green channels.

Cutting the red channel luminance in half results in a perceptual lightness reduction of only 31% or often much less depending on the other colors involved. In the case of max red at #FF0000, the equivalent is #B20000 which results in the perceived L* difference of 16, from L* 53.2 to 36.9 (31% lower) however #FFFFFF to #B2FFFF is only an L* difference of 5 (just 5% perceptually darker for FFF white).

This deuteranopia sim simply combines the red and green channels (the mixing is done after converting to linear, applying the standard coefficients, and some minor scale adjustments).

The Tritanopia simulator (blue deficient) essentially turns off the blue channel. To mimic the perceptual "feel" for normal observers, the red and green channels are combined, scaled, and sent to blue to balance the white point.

The last square is simply sRGB converted to Y (luminance, as in CIEXYZ). The sRGB is linearized, then the standard coefficients are applied, summed, gamma re-applied, and then sent to each of the R´G´B´ color channels. Note also that this simulator is using the true sRGB transfer curve instead of simple gamma for all of the simulations, and the sRGB colorspace is assumed for all simulations.

There are several images hosted here to choose from, or you can use your own image source. To use with your own images, just upload an sRGB JPEG or PNG image using the form below. sRGB colorspace is assumed — other color profiles will cause unpredictable and inaccurate results. Image size is limited to about 615px X 900px. Larger images will be resized and/or cropped as needed. Processing takes place locally on your machine so speed is dependent on your computer/device as well as image size.

And to be clear — this is specifically how CVD may see stimuli on an sRGB monitor. For a simulation of how CVD sees the world in general, Please see our main simulator, which is based on the Brettel studies.