Simulation

Physically correct sRGB → linear → LMS projection onto the dichromat confusion plane (Brettel 1997 / Viénot 1999).

const red = swatch("#ff0000");

red.simulate("protan");                       // full protanopia
red.simulate("deutan", { severity: 0.6 });    // 60% deuteranomaly
red.simulate("tritan");
red.simulate("achroma");                      // Rec. 709 grayscale

Accepted types

The severity continuum

severity 0.0 returns the identity (the original color). 1.0 returns the full dichromat. Values in between are a linear interpolation of the RGB transform matrix, matching the Machado 2009 model's behavior along the continuum.

red.simulate("protan", { severity: 0 });   // identity
red.simulate("protan", { severity: 0.5 }); // mild protanomaly
red.simulate("protan", { severity: 1 });   // full protanopia

Walk the slider in the §02 panel of the playground to feel it live.