MACRO PHOTOGRAMMETRY for the DAMAGE ASSESSMENT of ARTWORK PAINTED SURFACES

Abstract

In this paper we are presenting our approach and workflow for macro photogrammetry as a complementary method for 3D digitization of polychromies on wood support. Macro photogrammetry can be used for detailed documentation of physical damages in painting layers, underlayers or support. For a better presentation of the context, a selection of typical physical damages, relevant to this study, are explained. Two case studies are presented. Two wooden icons realized with different techniques and presenting different types of physical deterioration. The experiments detailed within this paper represent the first epoch of long-term monitoring of the restoration interventions for each of these icons. All the stage of our workflow is thoroughly detailed with acquisition parameters and processing settings in order to better understand the results and where things can be improved. For each icon a full body photogrammetry process is described, followed by macro photogrammetry on smaller selected areas on the icons' surfaces. Macro magnifications of 1 : 1 and 2 : 1 are obtained by using a dedicated macro lens and extension rings. Lighting setups and focus stacking process are also described for a better understanding of the parameters and settings used.