Image Documentation and Frottage

Subject: Archaeology. Course title: Documentation of Rock Art. Level: BA and MA. Course size: Suggested maximum 12 students per teacher. 

Motivation for the activity

The documentation and registration of rock art is not a regular part of the curriculum for archaeology students at either Bachelor or Masters level in Scandinavia. However, Prehistoric Art is found all over the world and is a ubiquitous feature of the Scandinavian archaeological landscape. As documentation and registration of rock art is not part of the practical skill set offered at either Bachelor or Masters level, there is currently a gap in the body of the broad range of skills expected by the major employer of Danish archaeologists; the regional museums.

One of the greatest challenges to integrate this skill at university level is that it is difficult to incorporate the practical element of rock art documentation and registration in the classroom. In this contribution, I explore some of the ways that this subject can be integrated into teaching and make a proposition for practical work.

Description of the activity

Participants of the activity will be introduced to skills in the documentation and registration of surfaces using frottage and image based modelling. This activity could be a component of several modules and would support course learning outcomes such as:

  • Demonstrating knowledge of recent developments in the understanding of prehistoric art in Europe.
  • Evaluating the investigation and management of rock art in everyday practice, with a focus on recognition, documentation and management.
  • Developing skills to record visual material.

Planning the activity in terms of practical elements is important. First of all, the teacher needs to identify suitable subjects for the practical work. These can be broadly subdivided between objects and surfaces.This is important to bear in mind as these different types of subject have slight variations in their specific requirements. In particular, the way of taking photographs for an SfM of an object is different than the acquisition of images for a surface.

The practical work of this activity can be divided into part 1: Frottage and SfM in field (pdf) and part 2 : Writing a good description (pdf). In relation to the activity the teacher should consider Source equipment (pdf) for frottage and SfM as well as prepare a concise help sheet for students, if desired. During this activity students will develop an appreciation of using a variety of methods and be able to optimize their recording strategies appropriately to the specific case. Through the practice of documentation, they will learn by their own successes, and failures, what factors affect the end result, and hence increase critical awareness on the subject. The exercise in the writing of a description will reinforce the role of objectivity in documentation and recording.

 

Points to bear in mind

The teacher needs to have following points in mind when doing this activity: 

  • A suitable subject to conduct frottage and SfM needs to be identified. Permission also needs to be granted from the owner.
  • If the group is over 8 persons, try and have one or more competent and knowledgeable assistants presents to assist. Queries do arise and feedback is easier to give to smaller groups.

  • The practical work is outdoor work, and subject to the variations in the weather. Surfaces should be dry for both frottage and SfM. Contingency plans need to be made (arranging to use indoor examples).

  • Students can use their phone cameras to take the pictures for the image based model. However, access to SLR’s or other kinds of higher quality cameras will considerably enhance the student’s ability to produce a better model and to gain more insightful feedback on the quality of their model.

  • In order for students to having the ability to process and save copies of the models they produce, they will need access to a licenced copy of PhotoScan.

Outcomes of the activity

The major outcomes of the activity are practical and the students will after the activity be able to:

  • demonstrate practical competencies in both frottage and image based documentation.
  • identify and execute the appropriate recording strategy for particular kinds of surfaces or objects within image based modelling.
  • acquire and apply in practice a working knowledge of PhotoScan processing software.
  • present 2D and 3D data in an appropriate digital format, such as a report or mini-report.
  • formulate, concise, objective descriptions of the subject or subjects being registered.
  • demonstrate critical awareness and reflect on the factors affecting the quality of documentation and registration material, including that produced during the practical.

Relevance of the exercise in other areas

The specifics of this activity are designed to form an integrated component of a larger course, focused on either archaeological methods / field practices or prehistoric art. However, the methods outlined in this contribution have a wider application both within and outside the field of archaeology. The suggested exercise in the recording of surfaces could equally be applied to the study of wall paintings, rune stones, grave stones as well as within more theoretical, technical, contexts aiming to gain experience in 3D image based modelling.

Acknowledgement

This resource has been developed in collaboration between Aarhus University and The Scandinavian Society for Prehistoric Art, Tanum Rock Art Museum and Research Centre, Underslös, Sweden. Thanks are extended to both the society and the museum for advice and supplying supporting materials.

Links and Extra Material

  • Moesgaard Museum for use of material in their museum district or in their collections.
  • The Scandinavian Society for Prehistoric Art, Tanum Rock Art Museum and Research Centre, Underslös, Tanumshede, Sweden; Email: adorant@bigfoot.com. Website: rockartscandinavia.com. Contact the museum for advice and professional expertise. This organisation was the first in the world to document whole surfaces using the frottage technique.
  • For an informative demonstration of the frottage method by museum director Gerhard Milstreu (Tanum Rock Art Museum and Research Centre) visit RockArtScandinavia's Facebook.

Supporting Frameworks

  • Milstreu, G. and Prøhl, H. (eds.) (2008) Documentation and Registration of Rock Art in Tanum, No. 3 Kalleby, Finntorp, Ryk. Göteborg: Göteborgs Universitet.

  • Interim Report (in Danish) produced during the RANE project for an activity at the museum NaturBornholm for school children. 

  • Agisoft website. Installers and user manuals can be found here. The user manual specifies how to take and process an SfM.

  • Bertilsson, U., Bertilsson, C., & Meijer, E. (2014). Dokumentation av Världsarvets Hällristningar med 3D teknik - Structure from Motion. Etapp 1. Pilotstudien på Aspeberget 2014. Rapport Svenskt Hällristnings Forsknings Arkiv. Retrieved from www.shfa.se 

SØG

The content of this page was developed by James Dodd, PhD Student in Archaeology, Aarhus University, specializing in prehistoric art, 3D modelling and GIS.Member of The Scandinavian Society for Prehistoric Art, Tanum Rock Art Museum and Research Centre, Underslös, Sweden.