1. K. Mouhoubi 1, S. Gomis 1, J.L. Bodnar 1, V. Detalle 2 1 GRESPI/ECATHERM, UFR Sciences Exactes et Naturelles, BP 1039, 51687 Reims cedex 02 2 LRMH, 29 avenue de Paris, 77420 Champs sur Marne

2. The contribution of lasers to the preservation of heritage Presentation of a new application of laser What do we know murals painting ? The experimental equipment used The theoretical approach The results

3. Nowadays laser are everywhere, their use are endless. In the field of heritage preservation here are some uses: The cleaning of the stone with the Nd YAG laser The analysis of compounds with the LIBS

4. We will present the possibility of a non-destructive technique to detect pigment deposition technique in the murals paintings by using a portable laser associated with a thermographic camera. Fresco or mural painting ? Localized excitation of the work of art using a laser Detection by means of a thermographic camera Analysis of the temperature response result

5. We will present the possibility of a non-destructive technique to detect pigment deposition technique in the murals paintings by using a portable laser associated with a thermographic camera.

6. Murals painting : Monumental decorative element forming part of a set architectural Origin: antique There are many techniques of murals painting : Generally pigments are mixed with an organic binder (glue, casein, egg) and deposited in a thin layer on a dry coating, it is the generic wall painting. Another family murals painting exists: the frescoes. The pigments are deposited directly onto a fresh coating and are embedded in the coating during a chemical reaction called carbonation... Wall CoatingPictural layer Murals painting Frescoes

7. Excitation : Laser Power : 3 W Wavelength : 810 nm. Detection Infrared thermography using a thermographic bolometric camera FLIR© SC645. The lens used : Field of view/min focus distance 25° x 19° / 0.25 m. Spatial resolution (IFOV) 0,69 mrad (640 x 480 px). Thermal sensitivity @ 50/60Hz 0.05° C at 30° C.

8. Log [Time] Log [Temperature] Typical behaviors Log [Time] Log [Temperature] slope failure

11. Response of a sample of PVC according to the radius of integration Ponctual Integration on R Integration on 2R Integration on 3R Integration on 4R

12.  Experimental results with two test lab coated black manganese Test specimens black Mn prepared glue and fresco Results Mural painting with glue Fresco

13.  Results obtained in-situ (Painted ceiling of the Chapel of St Martial, Palais des Papes, Avignon) Unrestored Zone: Temporarily out of early slope => Mural. Area restored: slope failure late => fresco technique.

14. It is possible to differentiate the murals painting to other techniques of fresco mural nondestructively using a laser shot and infrared detection. We have demonstrated that it was possible to characterize art techniques using a laser. We are currently working to improve the robustness and sensitivity of our device. Thank you for your attention