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Centre de Recherche et d'Etudes pour l'Art Préhistorique Emile Cartaihac

RESTITUTION: USING NEWS TECHNOLOGIES (3D, FILM ...)

3D Imaging and Cave Art

     For the last few years, 3D imaging techniques (three dimensional digitisation) have been applied to caves and shelters with increasing success as they offer a vision of Cave Art that is both in volume, attractive and available to everyone. In France, Cosquer (Bouches-du-Rhône) was the first cave to receive this treatment in 1991 thanks to a grant from EDF. Since then many sites have followed including, the carved shelters of Chaire-à-Calvin (Charente) and Roc-aux-Sorciers (Vienne), the Lascaux cave (Dordogne), Chauvet (Ardèche), Le Colombier (Ardèche), La Baume-Latrone (Gard), La Garma (Cantabrie), La Peña de Candamo (Asturies)...

     Up till now, 3D technologies have mainly been used in the final phases of study, offering a global vision of the site. Today, they offer vast new fields of experimentation and allow us to reconstitute monuments which are either gone or completely derelict. In terms of Palaeolithic Art, 3D imaging can even help to restore caves worn down by time or human vandalism. Dated to 15000 BP, the cave of Marsoulas (Haute-Garonne) was an ideal subject for this type of ambitious experimentation. To the best of our knowledge, a « digital restoration » of this kind had never been attempted before. It was made possible only by combining 3D technology and the scientific results of the graphic data collection. The same concept is currently being applied to the site of La Baume-Latrone.

     3D laser scanners are well adapted to the study of Prehistoric Art as this study requires maximum resolution in terms of images (resolution varies according to models). Points acquired by the use of a laser scanning the rock surface are immediately visualised as an array of points. Thanks to specific software, this array is triangulated: the points are mathematically linked to create a mesh of the scanned object, in this case the rock surface. The object that is thus triangulated or meshed will then have a texture applied to it. Matching, high-resolution photographs taken along the correct axis are then projected onto this mesh by using certain key reference points (so-called orthoprojection).

     The combined use of 3D technology, photography and drawings on transparent paper is proving to be a formidable evolution for the graphic translation of Cave Art as well as the rock medium on which they are depicted thanks to the creation of volumes. Light, shade or cracks which had to be represented by a 2D drawing are now immediately visible thanks to 3D technology. We are thus able to modify at will our point of view, the angle of the light to give a better understanding of the work in its context.

     New fields of experimentation are thus opening up to researchers in Cave Art who are aware of the need to preserve these caves by minimising their presence in situ.

     The project 4D-arte rupestre applied to the Spanish Levantine rock art is a nice application of these new technologies (see Etude de l'art post-paléolithique ibérique). The contribution of 3D and Gigapixel imaging is illustrated by an example from Solana de Las Covachas, which allows the use of natural relieves in the Levantine rock art to be perceived (see Giga-Dstretch).

Film and cave art

     From a very early stage, film was used to show the general public the beauty of Cave Art that was then the privilege of a few initiates. However, the complexity of the recording apparatus (camera, heat-intensive lighting) restricted such films to a few important sites. Among such films, we can note the TV series by Mario Ruspoli in the 70s, the documentaries by Jean-Pierre Baux on the caves in Quercy along with the group of caves in Niaux, Font-de-Gaume, Rouffignac and Pech-Merle, produced by the SFRS (Cérimès) in the 80s.

      Progressively, we have become aware of the interest of using animation to both create moving archives of Cave Art and to record images for experimental purposes. Several scientific and general public films (in collaboration with the Ministère de la Culture and the CNRS) have benefited from the progress in image recording (digital images, HD) which point the way to simpler recording techniques, using white cold light, and thus do not damage the subterranean environment. The film «Marsoulas la grotte oubliée» was made in close collaboration with scientists, film-directors and 3D graphic specialists (see below for an extract of this film)

      Given the miniaturisation of current video recording devices, film is today used not only for the study of the cave (acting as a 'notepad'), but also acts as a precise archive of the rock surface (HD offering optimal quality) and allows us to promote the site and the scientific work being carried out there (documentaries, fictions, streaming videos on the internet).

See an extract from the film "Marsoulas, the forgotten cave" (Marsoulas, la grotte oubliée), made by Marc Azéma and coproduced by Passé Simple, France 3 and CNRS Images.