: 400 to 700 nm range of wavelengths visible because those are the wavelengths to which our eyes are sensitive. That range reflects the wavelengths of sunlight which reach the Earths surface with sufficient intensity to excite the cells on our retinae. The cone cells of the human eye are sensitive to 3 wavelength ranges which the eye interprets as blue (narrow, with a peak near 419 nm), green (broader, with a peak near 531 nm) and red (also broad, with a peak near 558 nm, which is actually more like yellow).