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

METHODS RELATING TO GRAPHIC DATA COLLECTION

 

      More than any other Art form, Prehistoric Art needs to be deciphered to be correctly perceived. Often, erosion, nature or modern vandalism have lead to the degradation of some frescoes. With the passage of time, carvings made with flints or hammered on cave walls have become merely lines which are invisible without special lighting. Paintings made with mineral pigments have lost their brightness and seem almost dissolved into the rock face. These conditions force researchers to make a detailed analysis of the cave walls. The graphic information thus acquired allows us to visualise the painted or carved figures and to understand the techniques and time-scale involved in their creation.

      A similar method can be used for carved or painted objects, be they of animal origin (bone, deer antler, ivory...) or of mineral origin (schist plate, limestone blocks...). Their small sizes and their fragmented condition often force us to work on blown-up photographs of these objects (see the examples below of Gourdan and Limeuil).

      For 100 years, the methods for gathering information on Prehistoric Art have been constantly evolving as researchers look for an ever-increasingly accurate and objective rendering of the art works and their context. The first, very basic techniques (drawings made by using a transparent sheet of paper in European caves, lead pencil etchings of outdoor carvings, watercolours for cave dwellings...) have now evolved with ever-more complexity in order to answer the demand for ever-more precise data and the need to preserve all sites.

Theories, methods and techniques for graphic data collection

      In terms of Cave Art, collecting graphic information has often been compared to recording information on an archaeological dig; it is the only way to give meaning to what is discovered. The aim of this work is to offer a graphic interpretation that gives a true picture of the complexity of the facts that can be observed and hence create a document that acts as a complement to photographs. This task firstly requires an inevitable reduction in the amount of data; in other words, choices must be made as the amount of potential information on the cave wall is immense and too much information may lead to visual confusion. For example, data regarding the actual rock surface (calcite, cracks...) should not hinder our perception of the works of art. Likewise, graffiti and modern vandalism are recorded but not necessarily reproduced (see « Engraved bison from Marsoulas »).

      As is now the established rule, research is undertaken with no contact with the actual rock surface, on the basis of a photograph of this surface from which graphic information will be gathered in order to obtain a rendering of the work in question. This method offers a major advantage: by separating different types of data (engravings, red or black paint, surface variations, natural wear, etc.), we can easily select one particular type of data and hence visualise only the engravings or even visualise a work of art before it was damaged or destroyed (see « The great painted wall of Marsoulas » »). Graphic data collection can make visible what the naked eye cannot (or can no longer) see.

      Digital technology plays a fundamental role, not only for taking photographs (the resolution of the pictures is constantly increasing) but also thanks to digital improvement of the photographs (increased contrasts, chromatic corrections...).

      Graphic data collection forces the researcher to make a very close observation of the rock surface and to gather information from a variety of sources: techniques used, overlapping figures, state of the rock surface or of the pigments... The systematic recording of even the faintest traces allows us to identify paintings and carvings that have today almost vanished. In this manner, we are able to reconstitute, on a scientific basis, entire panels of the cave (see the sub-theme Restitution: using new technologies (3D, film...).

Examples of applications in Cave Art

Exemples of applications in Portable Art

Techniques of study used in the case of post-palaeolithic art in the Iberian Peninsula

      See the page devoted to the techniques of study of post-palaeolithic rock art of the Mediterranean Basin on the Iberian Peninsula