Illuminating means for illuminating a measurement surface and device for determining the properties of reflective objects. The illuminating means comprises a radiating means having radiation sources, an aperture means and a scattering means. The scattering means is arranged in the path of radiation and the light emitted by the sources of radiation is directable to the aperture means. The device comprises an illuminating means as a first optical means which radiates light onto a measurement surface. Said first optical means has a radiating means comprising radiation sources, an aperture means and a scattering means arranged in the path of radiation. The light emitted by the sources of radiation is directable to the aperture means. A second optical means is configured as detector means and registers the light reflected from the measurement surface. Said detector means outputs a measurement value which is characteristic for at least a portion of the light as received. A memory means is furthermore provided and a control means serves for the controlling of the measurement sequence, wherein a characteristic parameter which characterizes the measurement surface is determined.