Abstract: The invention provides a method of optically reading relief carried by the outside wall of a transparent or translucent receptacle. The method of the, invention consists:in illuminating the receptacle by means of an incident light cone supplied by a lighting system placed beneath the receptacle;in adjusting the width of the incident light cone to limit lighting at least to the portion of the outside wall that is provided with relief in order to avoid parasitic reflections;in picking up the reflected light beams by means of the pick-up element disposed beneath the receptacle and suitable for forming a plane image of the wall of the bottle; andin adjusting the field angle of the pick-up element as a function of the characteristics of the receptacle.