New Shoes for an Old Bed
Using Heritage Science to Conserve Queen Caroline's State Bed
Date: 13 September 2024
Author: Rosie Chamberlin and Moira Bertasa
Work on Queen Caroline’s much-loved State bed, which we care for on behalf of the Royal Collection Trust, continues at Hampton Court Palace and our attentions are now drawn to protecting the feet of this priceless historic object.
Here, Rosie Chamberlin and guest author Moira Bertasa share how the latest scientific technologies can enhance our conservation efforts. Specifically, they discuss how we are using 3D scanning to create protective covers for the Queen Caroline State bed feet.
Image: Planned protective covers. © Historic Royal Palaces
The Queen Caroline bed feet are in a fragile condition, which can be attributed to their age, open display, and vulnerable position on the bed. Because of their condition, conservation treatment options are limited.
When we came to conserve them, we therefore proposed that the bed feet have protective covers made to guard against dust, accidental damage, and handling.
Our conservation team employed advanced 3D laser scanning technology to capture precise measurements to ensure a perfect fit of the protective covers, without compromising the bed's integrity.
This work was made possible by the substantial investment of nearly £1 million from the Arts & Humanities Research Council capital funding programme, Capability for Collections.
The programme offered a rare opportunity to renew dated instrumentation at the HRP Scientific Laboratory and access new state-of-the-art equipment, including a handheld 3D scanner.
3D laser scanning is one of the most accurate measuring and documentation technologies. It combines a laser and a camera to create a digital model of an object or environment.
It is used for creating precise digital records of artefacts and buildings, which can be further used to generate virtual tours of heritage sites and exhibitions.
Image: Diagram showing how data is collected using 3D laser scanning. © Historic Royal Palaces
Recent examples of the benefits of 3D scanning can be found in the 3D models used for rebuilding and restoring heritage sites damaged by natural and anthropic disasters, such as the fire of Notre Dame de Paris in 2019.
So, how does it work? The 3D scanner sends out a class 1 laser beam (not harmful for either operators or artworks) which hits the object’s surface and reflects back to the machine.
The reflected signal can be measured based on the time it takes for the laser to return to the scanner, or by trigonometry using a camera able to localise where the laser spot has hit the surface.
Both procedures help to calculate the distance to different points on the object. This is used to create ‘point cloud’ data: thousands or millions of points that define the surfaces of the subject in detail within a digital space.
Image: Rosie Chamberlin (textile conservator) recording 3D laser-scanning data of the Queen Caroline’s State bed feet in the Science Laboratory. © Historic Royal Palaces
During this project, Queen Caroline’s State bed feet were de-installed and brought to the Science Lab, where we scanned each one using our cutting-edge equipment.
The individual scans were crucial to gather as much information as possible, recording every detail, including hidden parts such as the reverse, which can’t be seen once the objects are reunited with the bed.
We also made records of the feet in situ, as it was important to study the fit of the feet with other elements of the bed, such as the base moldings and valences.
This was fundamental for the correct design of the covers, which are needed to protect the objects from dust without risking damage by pressing on other parts of the bed.
Image: Moira Bertasa (heritage scientist) recording 3D laser-scanning data of the Queen Caroline’s State bed feet in situ in the Queen’s Bedchamber at Hampton Court Palace. © Historic Royal Palaces / Royal Collection Enterprises Limited 2024 | Royal Collection Trust
While our Science Lab is well equipped to undertake most conservation requests in-house, there are some we still need to commission out. This was the case for the production of the covers. We asked for support from specialists in the field, discussing the best procedure to put in place.
Using our 3D laser-scanning data, the experts recommended either 3D printing or CNC (Computer Numerical Control) milling and vacuum forming.
But how do we choose one or the other? It was challenging, yet as always in any conservation treatment, we needed to weigh up our options, balancing risk and benefit to the objects we care for.
3D printing is a new but well-established and precise method for object reproduction, and we were excited to add a bit of innovation to our approach. However, the printers are generally small, and only a few plastics are suitable for our purposes.
Additional steps would be required as extrusion lines are created during the manufacturing process, which would need to be polished out.
The plastics available are known to yellow quickly in Ultraviolet light, so we would need to add a protective layer such as a UV barrier varnish.
CNC milling and vacuum forming, on the other hand, is straightforward and allows us to create our covers in a plastic already investigated and suitable for use in close contact with artworks.
Image: Planned protective covers. © Historic Royal Palaces
We are currently collaborating with an external company to create the protective bed feet covers using CNC milling. This process involves inputting our 3D scan data into a CNC mill to cut a replica of the bed feet from a raw material.
This replica will then be vacuum-formed (have plastic heat set around it) to create conservation-grade covers that are both strong and visually discreet, allowing visitors to appreciate the intricate carving of the bed feet without obstruction.
This is the first time our conservation team have used in-house 3D laser scanning and external CNC milling and vacuum forming. We hope this work will inform and provide effective solutions for future projects in our work programme.
This collaborative effort, involving textile conservators, heritage scientists, and external specialists, highlights an innovative approach to preserving historical artefacts.
We are planning to travel to oversee the manufacturing process of our protective bed feet covers to ensure they meet both our project brief and conservation standards. This journey will also allow us to learn how these new processes are being utilised in the heritage sector.
Next time you visit Hampton Court Palace, make sure to look out for the protective covers on Queen Caroline’s bed feet in the Queen’s State Apartments!
Project Lead: Rosie Chamberlin, Textile Conservator
Collaborator: Moira Bertasa, Heritage Scientist
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