Most CVD Simulators Skip sRGB Gamma. That Makes Red Two Stops Too Dark.

Pure red (#FF0000) in sRGB has a linear-light value of 1.0, not 0.2126. Skip the IEC 61966-2-1 decode and Brettel 1997 protanopia returns #4F4F4F instead of #828282 — a relative-luminance error of about 6×. This simulator does the gamma decode through a 256-entry LUT, runs Brettel / Viénot / Machado in linear-light, and refuses to apply Viénot to tritanopia because the 1999 paper says so.