In the present survey, we have analyzed Roman paintings in two rooms in a villa at El Ruedo (Almedinilla, Cordoba, Spain). We used different techniques and procedures. We such as X-ray diffraction and diffuse re established parameters that define colours in every international system. The diffuse reflectance techniques allowed us to identify the pigments, emphasizing that their mixtures are usually based upon a single chromatic pigment. (c) 2005 Wiley Periodicals, Inc.