Wien's displacement law states that the
black body radiation curve for different temperatures peaks at a
wavelength inversely proportional to the temperature. The shift of that peak is a direct consequence of the
Planck radiation law which describes the spectral brightness of black body radiation as a function of wavelength at any given temperature. However it had been discovered by
Wilhelm Wien several years before
Max Planck developed that more general equation, and describes the entire shift of the spectrum of black body radiation toward shorter wavelengths as temperature increases.