The present invention relates to a device (10) for determining a bidirectional reflectance distribution function of a subject (S) comprising: a light source (LS) for producing an incident light (li) and directing said incident light (li) onto a subject (S) at a predetermined zenith angle (θi) and at a predetermined azimuth angle (φi); means for displacing said light source (LS) at any location on the periphery of a hemispherical area centered on the subject (S); means (C) for measuring the bidirectional reflectance distribution function of the subject (S) from one fixed location, said fixed location being preferably aligned with a normal direction (Z) defined by the subject (S); a control unit adapted to control said displacing means and/or said measuring means; wherein said displacing means comprises: an arc-shaped arm (12) at one end of which is fixedly connected the light source (LS), said arc-shaped arm being slideably connected to a first support (14) through sliding means, thus permitting the adjustment of said zenith angle (θi); and means for pivoting said first support (14) about said normal direction (Z), thus permitting the adjustment of said azimuth angle (φi).