Abstract: A method and a device is disclosed for illuminating a sample (1) and/or reference and collecting diffuse reflected and/or transflected radiation from the illuminated element and delivering it to a measuring equipment. The illuminating means (2A to 2H), when illuminating a sample or a reference, provide an extending illumination, coming from at least two positions. A movable reflecting element (4) is provided such that it in one position reflects the light from the illuminating means (2A to 2H) onto the sample or reference to be irradiated and reflects the diffuse reflectance and/or transflectance from the sample or reference to means (3) collecting the radiation.