Conservation (and a 3D Scanner!) Comes to the Castle
This post was first posted on our sister blog, Castle Curiosities.
In early May 2022, the science lab of the Bader International Study Centre (BISC) became the nexus where hundreds of artefacts with drastically different histories, material properties, and provenance all came together. Iridescent glass fragments, WWII Royal Air Force porcelain, and archaeological iron horseshoes, all found on the grounds of Herstmonceux, currently occupy the same space as a large collection of Roman artefacts on loan from local Bexhill Museum. The former, temporarily removed from the Castle’s Visitor Centre, have been assessed, documented, and digitised by graduate students in Art Conservation and in Digital Media, and the latter, catalogued by undergraduates participating in the BISC Archaeology Field School.
Melissa Allen, Caroline Longo and Antonia Mappin-Kasirer hail from the Art Conservation program at Queen’s University, Kingston. They arrived at Herstmonceux Castle, toolkit in hand, keen to assess and document the Visitors’ Centre artefacts, and to stabilise the most fragile objects. Eager to digitise and immortalise these objects through 3D imaging and 3D printing, Julia Le Clair, an expert in digital media creation, flew across the pond from Toronto Metropolitan University with a state-of-the-art 3D scanner. Two weeks of dedicated time with these artefacts fostered an interdisciplinary methodology that combines conservation and digital technology. Through collaborative documentation, several precarious objects have been effectively frozen in time — rendered in a three-dimensional digital space to give viewers across the globe access to the Herstmonceux artefacts and their connected history. Julia, Melissa, Caroline, and Antonia also had the pleasure of delivering a guest lecture to the Archaeology Field School students; they discussed their work at the castle, their combined methodology, and the exciting intersection of conservation, archaeology, and digital media.
Dr. Claire Kennan, Research Coordinator for the BISC, and Dr. Andrew Moore, Research Coordinator for the Environments of Change project, supervised the students during their time at the castle. This work advances the research agenda and would be impossible without the continued support of the interdisciplinary research project Environments of Change: Digitising Nature, History & Human Experience in Late Medieval Sussex (medieval-environment.com), led by Prof. Steven Bednarski. This project, of which the BISC is a foundational partner, is funded by the Social Sciences and Humanities Research Council (SSHRC) of Canada and builds transposable frameworks and tools to interpret through digital technologies the relationship between humans, nature, and cultures.
The conservation students initially worked with packing materials found on site to remove artefacts safely from their cases in the Visitors’ Centre and to transport them to the BISC science lab. They conducted a survey of materials and then implemented a cataloguing system for the artefacts. As the students recorded and photographed the artefacts, they also assessed their condition, treatment needs, and storage and display requirements. While these considerations, carried out by trained conservators, are the foundation of standard condition assessments, the suitability of each artefact for 3D scanning was a new and exciting addition to their characterization. Structural stability, sensitivity of the surface, suitability, and historical significance of each artefact were priorities for the MA students when deciding which objects to scan. Furthermore, some physical aspects of the objects, such as darkness, sheen, and transparency, complicated the process and required consideration when selecting artefacts to scan. Finally, the students considered whether the process of scanning, and in some cases printing, would add value to the artefact by enhancing viewer engagement and making handling more accessible.
A highly corroded iron horseshoe was one of the more challenging objects the team encountered. It was excavated in 2017 by BISC Archaeology Field School students at the site of the old stables on the Herstmonceux Castle grounds. The Conservation students consulted archival records, where they found x-radiography of the horseshoe in its state upon excavation. Comparisons of these records to the current object made it clear that active deterioration was ongoing, and progression of corrosion had completely compromised the structural stability of the horseshoe. With every careful touch, small flakes of metal from the artefact were lost. It became clear to the conservators that the integrity of the artefact would be seriously compromised unless they addressed storage and treatment immediately.
The opportunity to scan the horseshoe in its current condition could not be missed. To capture the artefact on the brink of loss and move it into a digital space would allow the public to engage with it indefinitely, despite its physical inability to be handled safely. While treatment completed by the Conservation students would considerably slow down degradation, it also irrevocably alters the artefact’s visual appearance. After minimal consolidation – light and reversible adhesion in areas vulnerable to flaking – the object was carefully mounted, with sponges and foam as supports, for scanning. Through the combination of these methods, slight digital retouching, and multiple scans in varying positions, the horseshoe was preserved in a transmedial space of both the physical and digital.
After the group addressed initial assessments, our digital media specilaist, Julia Le Clair, began preserving digitally the artefacts through 3D scanning. This process analyses real-world objects to collect specific data on their shape and appearance, which can then be reconstructed through digital 3D models. Once the conservators deemed an object structurally stable, they placed it upon a rotating turntable to be illuminated by floodlights and captured through the Artec Space Spider, a powerful high-resolution 3D scanner based on blue light technology. The Artec Scanner allowed the digital media specialist to scan up to 7.5 frames per second and to record the intricate details of the artefacts with an impressive 3D-point accuracy of 0.05 millimetres. They accounted also for the texture of these artefacts, in order to allow for full-colour 3D scanning to create a photorealistic texture for easier replication and to provide even more avenues of possibility for the creation of a digital archive.
Unlike a typical camera, which is limited to taking photos and collecting information on unobstructed surfaces from their field of view, 3D scanners also collect information describing varying distances of an object’s surface. Combining these distance points, data, and “pictures” allows the scanner to record and create three-dimensional positionings. Once an object was scanned at multiple angles and directions to cover all its aspects, the digital media specialist was then able to clean, modify, align, correct, and merge the multiple scans and create a texturally and visually accurate 3D model for each artefact.
Before departing, the conservators devised new housings to provide long-term care for the Herstmonceux artefacts when they are not on display. This work preserves these objects for generations to come and contributes, alongside assessments and digital cataloguing, to knowledge-building about past materials, techniques, and uses of these objects. The conservators also reported to the BISC recommendations for the conservation treatment, display, and storage conditions of the artefacts; they recommended based on their expertise, as well as empirical data acquired from environmental data logging devices installed to monitor changes in temperature and humidity in the Visitors’ Centre display cases. This innovative collaboration between emerging conservators and a digital media specialist has provided an invaluable experience for the students involved, as well as outcomes that will positively impact Herstmonceux Castle for many years to come.
Melissa Allen, Julia Le Clair, Caroline Longo, Antonia Mappin-Kasirer, and Andrew Moore.