What you’re finding is the CIE “color matching functions”, which is closely related but not the same thing as the raw physical response of the cones. Here is a

What you’re finding is the CIE “color matching functions”, which is closely related but not the same thing as the raw physical response of the cones. Here is a paper describing the difference, and more current research than what you found: https://hal.archives-ouvertes.fr/hal-01565649/document https://hal.archives-ouvertes.fr/hal-01565649/document Look specifically at page 2, and the linear relationship between the color matching functions (where red has a left-bump), and the “fundamental sensitivity” plot, which is attempting to find raw physiological cone response to different wavelengths, rather than what the observer perceives.