The colorful decoration of statues and buildings in antique times is commonly described by the term Antique Polychromy. It is well known among scholars but less so in the interested public and its exact form is subject of ongoing research. In this paper we discuss results obtained from the Frieze of the Siphnian Treasury from the Sanctuary of Delphi (Greece). We will present the first applica-tion of a mobile instrument for macro-XRF imaging in the investigation of the Antique Polychromy and show that it allows to find significant traces not visible to the naked eye and not detectable by XRF spot measurements or any other mobile, non-invasive method. These findings allow for a partial reconstruction of the polychromy. Further, we present a novel approach to correctly interpret artifacts resulting from changes of the detection geometry in the investigation of complexly shaped samples by XRF imag-ing. This approach is based on the 3D surface model acquired by photogrammetry and fundamental parameter calculations.