Color Blindness Check

This calculator applies three separate linear-matrix approximations to your RGB color, one per color-vision deficiency, then reports a relative luminance figure alongside them. For protanopia and deuteranopia (the two red-green deficiencies), the Protan R/G and Deutan R/G outputs are each a weighted blend of your Red and Green channels -- 0.567R + 0.433G for Protan R, 0.43R + 0.57G for both Deutan R and Deutan G (the same formula is used for both, which is the whole point: red-green color blindness collapses the red and green channels toward the same perceived value). Red is weighted more heavily than Green only in the Protan formula (0.567 vs 0.433); in the Deutan formula Green actually carries the larger coefficient (0.57 vs 0.43). Red still moves both sets of outputs the most in practice, but for a different reason in each case: for Protan it's the coefficient, and for Deutan it's simply that this calculator's default Red value (220) is much larger than its default Green value (60), which outweighs Green's larger coefficient.

The Blue channel never enters any Protan or Deutan formula at all -- Blue passes through unchanged (Protan B and Deutan B literally equal your input Blue value) because protanopia and deuteranopia are red-green, not blue-yellow, deficiencies. Tritanopia (blue-yellow deficiency) works the other way: Tritan R equals Red unchanged, Tritan G equals Green unchanged, and only Tritan B is shifted, blending 95% Green with 5% Blue. This is a simplified educational approximation, not the full Brettel/Vienot LMS cone-space simulation used in professional accessibility tools -- it does not model gamma correction or the actual cone confusion lines, so treat the shifted values as a rough guide to red-green or blue-yellow ambiguity, not a certified accessibility test.