Studying transportation effects on canvas paintings by full field digital holographic techniques

Digital holographic speckle pattern interferometry (DHSPI) is a tool that retrieves the mechanical reaction of a work of art after a shock or vibration, perhaps as a result of mishandling. It provides a method for the assessment of the impact of transportation and reliable risk analysis. In order to assess the effect of handling and transportation on canvas paintings, an investigation was conducted at Bern University of Applied Sciences, University of the Arts, Conservation and Restoration employing DHSPI. Samples of canvas were used for a series of measurements simulating transportation vibrations. The surface deformation topology of the samples was studied with DHSPI in order to acquire information about all the alterations caused on the canvas samples by the vibration ‘fatigue’ (i.e. the repeated deformation due to vibration). Crack maps, provided by analysis of the DHSPI measurements, illustrate the crack growth with time. Risk areas, located before any vibration loading, also proved to be those most likely to develop cracks. The tests of the transportation of canvas paintings have been successful in detecting cracks and areas with defects, and also in monitoring their propagation with high precision.