Radiation is irradiated by an irradiation device at a pre-set angle of incidence with respect to the surface onto the surface to be investigated, and the radiation scattered and/or reflected by this surface arrives at a radiation detector device arranged at a pre-set detection angle with respect to the surface and having an image-recording unit which records black-and-white images, wherein this radiation detector device permits a spatially resolved detection of the radiation reaching it. The irradiation device directs radiation in a first wavelength range onto the surface and the image-recording unit records a first spatially resolved image of this radiation scattered and/or reflected from the surface and the irradiation device directs radiation in a second wavelength range onto the surface and the image-recording unit records a second spatially resolved image of this radiation scattered and/or reflected from the surface.