Wien's displacement law, illustration. Graph showing the change in the peak wavelength (horizontal axis, in nanometres) with intensity (vertical axis) for black body thermal radiation. As the temperature decreases (here from 7000 Kelvin to 4000 Kelvin), the peak wavelength increases. This inverse relationship is known as Wien's displacement law, and was derived in 1893 by the German physicist Wilhelm Wien (1864-1928). The term Wien's displacement law also refers to the overall changes with temperature.