Case Study 31
The value of metric drawing
Ian G Scott
The Ballochmyle study of cup- and ring-marked rocks by AOC Archaeology group in 2015 for Forestry Commission Scotland at last provides us with an excellent demonstration of the comparative values of drawing, 3D laser scanning and photogrammetry (see Ballochmyle: Case Study 24). However, even if we can afford to develop the results of laser scanning further, we must still concentrate resources on the training of personnel skilled in the interpretation of observations and in the methods of recording. As with botany, surgery and architecture these observations are expressed most readily by drawing, in the first instance using pencil and pen. One particular use of drawing can be demonstrated by reminding ourselves how this method of recording carved stone fragments is not only academically useful, but encourages the reconstruction of easily understood representations of how fragments would have worked together in the past.
Trained draughtspersons can combine information from many sources to record what has been observed. These sources include written notes and comparisons with other carved stones. As a result new conclusions can be reasonably based on this graphic record, which I have called a visual index or inventory. I would suggest that the first priority of research on medieval carved stones should consist of comprehensive scaled, measured drawings of elevations of all fragments supported by photographs and 3D scans, where these are available. Below I give some examples of where closely observed metric drawings in pencil and pen has led to new discoveries or changed interpretations.
Examples of drawn reconstruction:
• St John’s Cross, Iona: While most fragments had already been identified, two new ones were added because they were recorded using a consistent technique during a comprehensive review (RCAHMS 1982). One of these was the cross’s central boss, previously disregarded.
• St Matthew’s Cross, Iona: A previously unnoticed fragment was drawn and subsequently seen to be the arm of this cross through comparison with an early engraving.
• St Oran’s Cross, Iona: Fragments were already identified, but now have been drawn together. These three crosses now form an impressive centrepiece of HES’s site museum.
• Nigg cross-slab: A new fragment was incorporated in a drawing used to reconstruct the slab, and from a newly found drawing of 1822 we should be able to add more detail to the drawing in the future.
• Hilton of Cadboll cross-slab: I had already drawn the upper portion housed in the NMS when the lower portion was excavated along with its many thousands of fragments. These, if drawn in detail, could be added to the original drawing to define as much as could be reconstructed of the whole.
• Forteviot fragments: After the collection on site was recorded and drawn they were re-interpreted as belonging to three crosses, one using an existing cross-base. Subsequently the SERF project has instigated their display (see Cradle of the Scots: Case Study 19).
Figure 1: The front face of the Hilton of Cadboll cross-slab, reconstructed from some of its many fragments by Ian G Scott. Crown Copyright: Historic Environment Scotland
Figure 2: Ian G Scott working on the Nigg cross-slab. Crown Copyright: Historic Environment Scotland