Posted on February 1, 2024 by raep

The South West Heritage Trust (SWHT) has been working in partnership with the Digital Humanties Lab at the University of Exeter to create interactive digital models of the Cheddar Brooch. Rae Pearson, Digital Heritage Apprentice for SWHT, explains the process.

Cheddar Brooch

The Cheddar Brooch was found by metal detectorist Iain Sansome in Cheddar on 14 October 2020. Made of silver and copper alloy, the brooch dates to AD 800 to 900 and is 91mm in diameter. It is decorated in what is known as the ‘Trewhiddle’ style and has a unique design made up of detailed interlaced plant and animal forms in bright silver and black niello set against a gilded back panel.

The Cheddar Brooch (Photograph: Somerset Council and South West Heritage Trust)
The Cheddar Brooch (Photograph: Somerset Council and South West Heritage Trust)

Visit to the Digital Humanities Lab

Since acquiring the brooch in 2023, we have been planning how we can best showcase its intricate design. On the 22 January 2024 we visited the Digital Humanities department at the University of Exeter to have photogrammetry and reflectance transformation imaging (RTI) done on the brooch with the intention of creating interactive digital models.

The Digital Humanities Lab at the University of Exeter (Photograph: South West Heritage Trust)
The Digital Humanities Lab at the University of Exeter (Photograph: South West Heritage Trust)
The Digital Humanities Lab at the University of Exeter (Photograph: South West Heritage Trust)
The Digital Humanities Lab at the University of Exeter (Photograph: South West Heritage Trust)

Photogrammetry

The first stage of our visit was to have photogrammetry done on the brooch. The brooch was delicately propped up  on a rotating disc, which was then moved very slowly to allow hundreds of photographs to be taken of all sides. The software then started to build up each layer of a digital representation of the brooch in extreme detail. This digital model will  be worked on and processed until it is as realistic as possible.

Graham Fereday, part of the Digital Humanities Team at the University of Exeter, photographing the Cheddar Brooch (Photograph: South West Heritage Trust)
Graham Fereday, part of the Digital Humanities Team at the University of Exeter, photographing the Cheddar Brooch (Photograph: South West Heritage Trust)
Graham Fereday feeding the images of the Cheddar Brooch into the 3D model (Photograph: South West Heritage Trust)
Graham Fereday feeding the images of the Cheddar Brooch into the 3D model (Photograph: South West Heritage Trust)
The 3D model of the Cheddar Brooch in its early stages (Photograph: South West Heritage Trust)
The 3D model of the Cheddar Brooch in its early stages (Photograph: South West Heritage Trust)

Reflectance Transformation Imaging (RTI)

Next, the brooch was set up under a RTI dome made up of three layers of lights.  A timer was  set to take high resolution photographs of  the object as it was lit by each of the lights in turn. The lights highlighted the details on the brooch from all angles. After some processing, this allows the viewer to run their finger or a cursor over the image to change the direction of the light so that they can examine different areas of the object on a much larger scale.

See the Results

You can view the RTI model on the Cheddar Brooch webpage. 

Julia Hopkin, Data Support Officer at the University of Exeter, positioning the Cheddar brooch under the RTI dome (Photograph: South West Heritage Trust)
Julia Hopkin, Data Support Officer at the University of Exeter, positioning the Cheddar brooch under the RTI dome (Photograph: South West Heritage Trust)
Julia Hopkin setting up the RTI process (Photograph: South West Heritage Trust)
Julia Hopkin setting up the RTI process (Photograph: South West Heritage Trust)

 

3D Printed Replicas

Our next steps will hopefully be to develop 3D printed replicas of the Cheddar Brooch so that visitors will be able to handle the brooch and feel the details in a way that they would otherwise not be able to. We also hope to use the digital model in  a digital exhibition.

Acknowledgements

Thank you to Graham Fereday, Julia Hopking and Gemma Pulton of the Digital Humanities Lab at the University of Exeter for their technical expertise and support, without which this project would not have been possible.

The Cheddar Brooch was purchased with support from the Arts Council England / V&A Purchase Grant Fund, Art Fund and the Friends of the Museum of Somerset.

Two 15-month Digital Heritage Apprenticeships have been funded through Arts Council England’s National Portfolio Organisation programme. The apprenticeships are designed to enable young people to gain skills in digital engagement and to provide a pathway to a career in the creative industries.