Inora Newsletter #43
RESEARCH ON THE RECORDING OF ROCK PAINTINGS
IN THE KAPOVA CAVE (URALS)
On starting the study of the Kapova cave in 2002, I had the following objectives:
To carry out detailed photographic research on the known paintings in the cave;
To try to find new paintings and paint markings;
To develop new research methods for documenting painted rock art and its digital processing.
A documentary study of a historic monument implies the most complete description possible with a view to later studies. In fact, the first step consists of two types of work: making accurate copies of drawings or paint marks and describing them topographically (their position on the wall, their dimensions, state of conservation, characteristics of their pigment, state of the wall, etc.).
From June 2002 to August 2004 I made five visits to Kapova cave, representing nearly five months of work in total. During those stays I took over 3,000 photographs. The results can be summarised as: 1) In general, nearly 200 drawings and paint markings were observed.
2) A new method of analysing the drawings, recording them and later digitally processing them was developed. This method gives exceptional results as shown by the quantity of new drawings and paint markings found in the cave. Apart from this, thanks to the digital processing of the photos, I was able to decipher (“read”) certain designs before considered as “vague paint marks”.
3) All the already known and newly found designs were photographed and described as planned.
During the documentation of each paint mark, drawing or group of drawings, I tried to obtain the maximum information possible. Photographs were taken on different scales. First I photographed the wall on which a drawing or paint mark was found, then a larger-scale close-up and then details.
Each drawing or paint mark was photographed five times, with different lighting parameters. I used direct light, slanting light (with different angles in relation to the wall) as well as very bright light, a diffuse light and reflected light. One of the photographs, generally that in bright light, was always made with a metric and colour scale. This is because the drawings or details of an individual drawing could always be more or less “read” in relation to the type of light. In addition, the different light characteristics enabled the wall’s micro-relief (frequently used by the artist) to appear in the photo.
With the aid of specially developed scales, I tried to classify the drawings and paint markings according to their spectral characteristics; this seems useful for identifying and possibly dating the creation of different groups of drawings. Even though, in most cases, I used a metric scale, the method of spectral characterisation with the scales developed seems worthwhile and is relatively cheap.
All possible means of study were taken into account. Each drawing or paint mark was photographed with a view to later digital treatment. This meant that the photographs followed certain rules: Each photograph was made with a neutral calibration field:
1) All photos were made with a 50 mm focal length lens to avoid the risk of spatial distortion. However, some designs, such as those from the Chamber of Signs, could not be photographed with such a lens because of their position in the cave. In such a case the focal length used is specified.
2) All the photographs were made under different lighting. Certain types would enable a better later decoding of the image and “reading” of the wall’s microrelief. The different types of lighting are also necessary to create animation (as we will see later).
3) Certain drawings were photographed during each of the five visits to the cave with
the same photographic parameters to provide a seasonal study of the state of the designs. All the shots were made with a standard non-digital camera. The main reason for this choice is that such cameras have a greater dynamic range, which contributes to more complete information concerning the spectral and light characteristics of the drawings.
Digital Processing of Shots
After being developed and digitalised the images were given digital spectral filtering. This process is based on a division of the signal into spectral and light components. First, the light signal is separated from the spectral one; then the spectrum is divided into narrow bands. In certain spectral fields, where the image needs better definition to be clearly seen, the signal is increased. In other words, the processing consists of a progressive elimination of noise (in terms of digital images this is often found in dark-coloured zones), that is recognised as such if it does not correspond to a spectral zone being processed. Apparently, this image-processing method has no equivalent in archaeological practice, according to Professor Abraham Stoliar of Saint-Petersburg State University and our French colleagues (specialists in conservation) Jacques Brunet and Philippe Malaurent during their work at Kapova during the summer of 2004. Such photographic processing has only been possible with the advent of digital photography and was unthinkable when only analogical photgraphy was used.
Additionally, this documentary research method is free of risk for the drawings; there is no direct contact with them. Also, no reworking or correcting of the image structure is allowed.
In particular, digitalisation enables the isolating of, for example, ochre in a drawing on its wall and to present both separately in two different photographs (Fig. 1-4) 1. This result can only be achieved by this means. It is even possible to distinguish ochre from charcoal or clay. This could also be useful for dating certain drawings or paint markings. Thus, on one drawing from Kapova, it became possible to identify two different ochres from their spectral characteristics. In the Chamber of Signs, there are also some drawings whose spectral analysis suggests a palimpsest, that is, reworking or different superimposed coats of paint.
This processing method enables a better reading of “paint marks”, common in caves all over the world, and could (and should) finally replace the traditional pencil drawings, common in publications until now. In addition, it might also enable the finding of new designs which are not very visible.
The analysis of the Kapova designs produces a considerable difference in the spectral composition of paint on diverse surfaces. Sometimes, drawings on the same panel need different filtering parameters. The degree of destruction of the drawings or the different colorants in their paint could be responsible, and this might testify to their different eras of creation. To formalise this research a lot more studies are necessary in collaboration with all sorts of specialists: archaeologists, geologists, chemists, specialists in photospectroscopy, etc.
Apart from spectral and frequency filtering, I have developed a method of digital animation which has provided interesting results. I had the idea of imitating daylight. To do this, during a winter 2003 visit, I photographed several designs in a particular way and composed an animated cartoon. The result was extraordinary: it gave another way of reading the designs. Sadly, this animation cannot be presented in a journal as it requires a computer. I hope to find a means of “freezing” the results of a similar animation to be able to present them on paper.
After two years of work, the data base holds over 200 drawings and paint markings, while the most recent figure published was 50 (Scelinskij 2001).
My classification, according to the type of colorant and the way it is applied on the wall, is the following:
1) Designs painted in ochre 2 these are drawings or paint marks which are red-coloured and mostly have a weak yellow contour. They are in the majority in the cave.
2) “Polychrome” drawings their pigments contain other colorants as well as ochre. Principally they are black. These drawings or paint markings are much more vivid than those of the first type.
3) Black drawings more and more designs or paint marks of this type are being found. Sadly, their chemical composition has never been analysed and so it is impossible to classify them or to date them. This black could be charcoal or soapstone according to E. Devlet (2004).
4) Ochre designs on a sort of bas-relief in clay applied to the wall a spectral analysis showed the presence of ochre. The drawings or paint markings are very poorly preserved as the clay does not adhere very well to the limestone walls.
5) Finally, designs making use of the micro-relief of the wall sometimes natural projections or cavities show traces of being worked or corrected, which is a new element in the study of Kapova (Fig. 6).
Naturally, this article does not pretend to set out the principles of documenting rock art but it only presents my own experience and suggests one of the possible methods to carry out such research, which might inspire other researchers and also draw attention to the cave of Kapova in the Urals, little known in Europe.
The author is deeply grateful to Leonid Ilyine and Youri Liakhnitski for their continued help at Kapova.
Société géographique russe, Saint-Pétersbourg, Russie e-mail : firstname.lastname@example.org
Traduit du russe par S. RYNDINE. e-mail : email@example.com
DEVLET E. G., 2004. Altamira u istokov iskousstva. Moscou, Aleteïa, p. 164.
SCELINSKIJ V. E., 2001. Nastennoe iskousstvo verkhnepaleolititcheskogo sviatilistcha v pestchere Choulgan-Tach (Capova) na Youjnom Uorale : kompositsiïa « Lochadi i Znaki » v zale Khaosa. In Problemy pervobytnoï koultoury. Oufa,Guilem, p. 37.