Even if a precise, detailed geometry is essential for the study and documentation of a CH artifact, lots of information also comes from the color and appearance data. Since a complete reconstruction of the optical properties of an artifact is still hard to achieve, what is normally done is to rely on color data coming from photographic dataset.

In this paper, we will describe the tools that MeshLab offers for the generation and processing of color information on a high resolution 3D model. We will show the basic operations available and present actual projects were this tools have been successfully used.

The first step in the color management, is to align photos to the 3D model, this operation is possible in MeshLab in a short time by using a very simple interface. The photos aligned in this way may be spatially-explored directly in the 3D space, instead of browsing a folder on the disk, looking at the photos like see-through transparencies suspended in space or projected onto the surface.

An interesting possibility is to use also unconventional photos, like photos with annotations, historical photos or even near-visible lighting photos (ultraviolet, multispectral, infrared, thermography….)

The spatial exploration of the georeferenced photographic set is a powerful tool but, in many applications, it is needed to have the color information mapped onto the geometry. To this aim, MeshLab offers different color mapping tools to better cope with the different needs of the various datasets. By using the color data from the calibrated images, it is possible to generate detailed, artifact free per-vertex color encoding, fill an existing texture parametrization or generate an entirely new texture mapping, driven by the photographic coverage.

The reconstruction of a faithful representation of the actual color of an artifact is often just a first step towards the understanding of the original aspect of the object. Almost always, the current state of an archeological find is degraded: to propose possible reconstruction of the original color of the object is a normal activity for archeologists or art historian. This task, however, is generally carried out on photos or drawings of the artifact, while it would be possible to do it directly on the 3D surface.

The Surface Painting tools provided by MeshLab may be used to color the 3D surface using painting-like interface. By using this editing tool, it was possible to produce such proposed color reconstructions, directly on the 3D geometry.

MeshLab is the most complete open source software for the creation and manipulation od high resolution 3D models of real-world objects, and the availability of such color management tools is an important instrument for the archeological and CH community