Typical Reflectance Curves

Each color has its typical spectral curve. The color pigments absorb specific wavelengths of the incoming light, other wavelengths are reflected.Perfect white reflects the entire incoming light (i.e. no absorption) perfect black however absorbs all wavelengths at 100%.

If you add saturated dyestuffs to a white base specific sections of the spectral curve are lowered more and more.The spectral curve can never be raised by dyestuffs.