Blazed gratings are in general the best choice for achieving the maximal diffraction efficiencies in a moderate wide wavelength band. However, a number of applications such as typical spectrometer systems need a broader spectral range. Here the drop of diffraction efficiency for the employed order towards the edges of the addressed spectrum limits the dynamics of the spectral sensor system. Thus we present a systematic approach based on a combination of interference lithography and ion beam etching. It provides a tuneable spectral response curve even for imaging gratings by mixing the characteristics of different blazed angles without influencing the systems spectral resolution.