An apparatus for colour control of objects (11) has an approximately point-shaped light source in the form of a xenon flash lamp (16), which illuminates a specific, desired area through a diaphragm (17). Light reflected from the object is received by a detector unit (13) having three or more sensors (22) with their respective spectral sensitivities, which are positioned at such a great distance from the object that each sensor receives substantially the same amount of light from all parts of the illuminated area. The detector signals are amplified by amplifiers adapted to filter all signals exhibiting another timewise variation than the light source, so that disturbing influence form the surroundings is avoided. The apparatus is simple and fast and is versatile in use.