TRACCE no. 5 – by Belinha Campos
Observations on the use of two different rock art tracing methods at Vale de Vermelhosa (Côa area), during the project “Gravado no tempo – Portugal” (Etched in time – Portugal), lead by Mila Simões de Abreu and Ludwig Jaffe.
Although most people prefer it live, looking at a rock art site can be quite discourageable if one doesn’t really see it. Pecked figures like the ones at Penascosa and Canada do Inferno (Côa valley) are quite easy to spot, but the engravings found at Vale da Vermelhosa are delicate filiform (Palaeolithic and Iron age) with overlapping scratches, therefore more difficult to identify and understand. Because tracings are such an important feature in rock art recording, one of this project’s initiative was to have two kinds of methods out on the field. This experiment kept in mind the scientific legacy for future researchers, as well as the non-expert point of view. Both methods were never a threat to the preservation of the rocks’ surface (vertical schist panels) and the surrounding environment. Keeping these engravings the way they were found can be proven useful in the future, when more precise techniques will solve problems we can’t deal with now.
The first method to be tried up was conducted by Jane Kolber (Arizona Archaeological Society, Rock Art Recording Field School) and is based on the least possible contact with the engravings.
Several string grids are suspended on the rock, thus dividing the panel in 100×10 cm squares. Each grid has smaller squares (10×10 cm) that provide visual reference points. The information within this area is immediately reduced (scale 1.5) and drawn on the paper. The data (vegetation, lichens, cracks, colour readings, photo targets) is registered with pencil but the engravings are done black or coloured, meaning heavier patina or lighter patina. Other aids, such as magnifying glasses or other person’s tips can help straighten out doubts.
The fine filiform engravings at Vermelhosa required an accuracy not easy to match for a “visual” tracing. This method has proven best results on general rock sketching: it is ideal to illustrate the display of the engravings and the environment of the landscape they belong in.
The direct tracing method, co-ordinated by Andrea Arcà and Angelo Fossati of the Archaeological Cooperative "Le Orme dell'Uomo" ("Footsteps of Man"), is based on standard transparent plastic sheets (57x76 cm).
Just like in Kolber’s method, the sheets are held with Blue Tack which doesn’t leave residue on the rock.
The plastic is in contact with the surface while the engravings are traced. These are done from left to right, top to bottom, using special plastic pens, with different thickness and colours. The information recorded are the engravings (black), the main fissures (red), vandalism marks (green) and Blue Tack areas (blue).
After overlapping, each sheet is identified with a code (area/panel/sector/sheet number/date/author). Working in day light is an advantage to detect details. Shade and mirrors are manipulated to reveal scratches and improve tracing conditions. There was no need for artificial light. Reduction scale (scale 1:4 and/or 1:8) is done later, with photocopies and several assemblies that maintain quality.
This technique gives the most accurate copy of the engraved surface, even though it takes less information on the plastic sheets. Result are cheaper and faster to achieve without loss of resolution. Above all, this method solved the overlapping engravings problems found on the first panel of Vermelhosa site.
The employment of these methods at the same site brought up important issues.
Since the fight against the dam began, the Côa Valley rock art has been discussed world wide, and not only by rock art experts. The explanation given by these haven’t always matched the expectations of local people and common visitors. Some questions are yet to be answered. Meanwhile, the Côa Archaeological Park was set up to co-ordinate both scientific studies (in process) and public access. There is, however, a need to make this finding understood and so admired by common visitors. Kolber’s sketching, for example, can be very useful in panels and publications
that show people an informal point of view, instead of giving them a complete archaeological tracing. This suggestion would help diminish frustrate tourists and potential vandals.
Direct tracings have to be made for the sake of future studies. However, the truth they disclose is obviously recognised more immediately by researchers than by the general public.
It’s not about deceiving peoples expectations, but rather having a different, better way for them to know and enjoy the engravings.
Gravado no Tempo research team