An illumination apparatus is disclosed, comprising: a first light source having a first spectral light distribution with a first light intensity peak about a first peak wavelength, and a second light source having a second spectral light distribution with a second light intensity peak about a second peak wavelength being different from the first peak wavelength, a third light source having a third spectral light distribution with a main light intensity peak about a third peak wavelength being different from the first peak wavelength and from the second peak wavelength, wherein the illumination apparatus is configured to provide adjustment of light intensity of the first light source and of light of the second light source, wherein the illumination apparatus provides an adjustment of light intensity of the third light source to compensate for the adjusting of the relative light intensity between the first light source and the second light source.