Case Study: Reading the unreadable: use of photogrammetry on a 16th-century inscription

Case Study 41

Reading the unreadable: use of photogrammetry on a 16th-century inscription at Kirkmichael, Black Isle

Jim Mackay and Andy Hickie

Figure 1: The restored Kirkmichael church with is recessed tomb. © Andrew Dowsett

Figure 2: The Kirkmichael recessed tomb with its inscribed panel. © Jim Mackay

The community-led Kirkmichael Trust has undertaken an award-winning restoration of the mausolea at Kirkmichael, Highland. As part of our ongoing research we have been experimenting with the latest photogrammetric techniques to excellent effect. The church was erected in the early 1400s, long before the Reformation, but the existence and survival of a pre-Reformation feature such as an arched tomb, more associated with cathedrals than protestant kirks, is surprising and has long attracted attention. The church was shortened when converted to mausolea for local estates and this tomb, now outside, was once inside the nave. Set within the arched tomb is a sandstone panel bearing an inscription. We suspected this was a later insert, but we could not tell. It is eroded, so that igneous intrusions, once below the surface, now protrude. However, the words always seemed to us to be almost readable.

Figure 3: Kirkmichael inscribed panel recorded using night-time lighting. © Jim Mackay

We had previously photographed the panel using oblique light. This picked out some letters, and perhaps the word ‘AND’, but nothing was certain. We then used an LED floodlight at night, usually successful on worn inscriptions, and more letters appeared but still no definite words.

Figure 4: Photogrammetry reveals the secrets of the 16th-century Kirkmichael inscription. © Andy J. Hickie

Enter Andy Hickie of the Avoch Community Group, who had been experimenting with a novel photogrammetric technique which has received recognition from the Corpus of Anglo Saxon Stone Sculpture. Andy realised that Red Relief Imaging, originally developed by Asia Air Survey Ltd for displaying LIDAR data, could also be used for analysing point cloud data derived from standard photogrammetry, and has adapted the technique for use on stone carvings. Applying this method to the Kirkmichael inscription, words began, as if by magic, to emerge

We have discovered that it is a panel erected in 1584 by John (IHONE) Urquhart to commemorate his parents. The lettering is remarkably consistent in depth and spacing, a quality piece of stone carving. It is in Scots, with ‘Q’ used for ‘quha’ (‘who’), ‘VMQ’ for ‘umquhile’ (‘late’) and ‘y’ for ‘th’ as in ‘ye’ (‘the’) and ‘yis’ (‘this’).

The central section reads ‘HIS VMQ FATHER RONALD VRQ/IN FERRITON Q ***TIT YIS LYF YE 28 OF SEPTEBER/1575 AND OF HIS VMQ MOTHER ELIZABET HALIBVR-/TON Q DEPTED YIS LYF THE 13 OF FABRVAR 1583’. Whilst John Urquhart of Ferryton crops up in a few documents of the period, his parents are never mentioned. This is new information.

 

Things to consider

  1. Photogrammetry is not an exact science. Different sections of an image are adjusted, darkened, lightened, repetitively, to get the clearest image.
  2. Photogrammetry cannot achieve miracles. Some words on the panel are still undeciphered due to the degree of erosion to the sandstone.
  3. The hours spent poring over images could not realistically be devoted to many stones. However, for the occasional special stone, it is a remarkably effective exercise in reading the unreadable.

The restoration of Kirkmichael has seen many stones repaired and rescued (Mackay 2018) and see Story behind the Stone on our website). This panel is now known to hold one of the oldest inscriptions bearing a date in the Black Isle. We need to consider further protection measures for this carving. We also need to consider which other stones could benefit from this photogrammetric technique.

Figure 5: Near forensic examination of the Kirkmichael inscription using photogrammetry. © Andy J. Hickie