3D model of the sarcophagus of Ulpia Domnina: rendering of stored ancient color and virtual revival of original polychromy

The aim of this work is to document the current condition of the polychromy of an Roman sarcophagus and to visualize hypotheses on its original state. The sarcophagus, dedicated to Ulpia Domnina, is dated at the end of the 2nd century A.D. - early 3rd century A.D. (inv. no. 125891) and is preserved in the National Roman Museum - Baths of Diocletian. It has been chosen because of the good state of preservation of its ancient color, which can reveal the used coloring techniques (see Figure 1). As a part of this work, a high-resolution digital 3D model of the artifact was created, by acquiring a point clouds using a triangulation laser scanner. This geometry sampling has been paired with a photo acquisition campaign. The resulting sampled data (geometry and color) have been processed and integrated using the Mesh-Lab open source system (see Figure 2), to obtain a faithful representation of the current state of the artifact. This digital model has been instrumental to the main objective of this project, that is to clarify the techniques and pigments used, and to explore the potentialities of emerging technologies to reach and validate objective conclusions. To this purpose, the 3D model has been used to spatially reference (like in a 3D GIS) the various information gathered during visual, physical and chemical analysis. Moreover, digital painting interface (use paint-like interaction directly on the 3D surface to define the appearance of the 3D model) and state of the art rendering techniques (both real-time and offline) have been used to generate reconstruction hypothesis of the original appearance of the object.