Rubbing is a method, where it is possible to document the contour of the images, and the surface of the rock. In this respect one gets informations about weathering of the surface and the images, slightly technical informations which can show if image(s) has been updated, since the time of creation.
To do a rubbing, you will need these items: Paper, tape, carbon-paper, a cloth and grass. You can use moss or soil to decorate the rubbing, if you want to make art. The cloth is rolled tightly up, and a carbon-paper is wrapped around the cloth (Photo Mette Rabitz, Tanums Hällristningsmuseum).
Step 1: After cleaning the surface with a broom, the paper is taped proper to the surface, and now the documentation can begin. Do a rough outline on the paper, by adding very light pressure to the carbon-roll. Afterwards rub systematically from one side. This photo shows the recognition (weak colour) + the systematic work beginning from one side (Photo Mette Rabitz, Tanum Hällristningsmuseum).
Step 2: The rubbing is fixated with fresh grass. It is the chlorophyll in the grass, which binds the carbon. Note: The rubbing with grass slightly darken the images, so be careful not to rub too much around the images, then you will end up with a result, where the images have a much stronger contour (Photo Mette Rabitz, Tanums Hällristningsmuseum).
The result (Photo Mette Rabitz, Tanums Hällristningsmuseum)
When rubbing an area, which takes more than one paper, it is important to make sure the colour on all papers are equal (Photo Mette Rabitz, Tanums Hällristningsmuseum).
Want to learn more about documenting rock carvings using the rubbing-method? Please visit Tanums Hällristningsmuseum: http://www.ssfpa.se/ which is the only Scandinavian institution that teaches fieldwork- and documentation of rock carvings!