Color Blindness Simulator
How colors look to people with a color vision deficiency: protanopia, deuteranopia and tritanopia. A strength slider from normal vision to the full effect.
An approximation, not a diagnosis.
Normal
unchanged
#FF0000
Protanopia
no red cones
#6D5F00
Deuteranopia
no green cones
#A39000
Tritanopia
no blue cones
#FF000F
How it is calculated
Each pixel is turned into linear RGB and multiplied by the 3 × 3 matrix of the deficiency (Machado, Oliveira, Fernandes, 2009; full strength), then back into sRGB.
The strength slider blends normal vision and the matrix: M = (1 − s) × I + s × M(1.0). The matrix rows add up to 1, so white and gray do not change.
RGB_out = M · RGB_linear M = (1 − s)·I + s·M(1.0)
Worked example
Pure red (#FF0000) under protanopia loses almost all its red: it becomes a dark brown-olive that is hard to tell from green.
An approximation, not a diagnosis: real perception depends on the person, the degree of deficiency and the screen.
Check a PDF