The paint samples are tiny – often just 1mm across. We take them using a scalpel to cause as little damage as possible to the work. We describe this as being ‘microinvasive’ – it leaves a tiny hole but is not usually visible to the eye. We put the samples in a liquid resin, and once the resin has cured, we polish and expose the stratigraphy – layers – of the sample. It’s a bit like cutting through the layers of a cake. When you look at them under the microscope, the layers can offer clues about the period the work was made, its provenance, the manufacturing processes used to make it, and sometimes even the artist.

I always say heritage scientists don’t answer the questions, they teach you what questions to ask.
I work with curators, conservators and historians to understand more about a sample and its history.  Then that context and combination of expertise and knowledge comes together to build the bigger picture.

The big ‘painting hiding under the painting’ reveals make for good stories, but they are quite rare. My work is more like that of a detective – gathering clues and connecting the dots. The stories the paint samples reveal might influence how conservators choose to look after an object or the decisions they make when they’re restoring historic places. For example, curators at the Bath Assembly Rooms, which are currently being restored ready to reopen in 2027, are using analysis of paint samples from the Card Room to help decide what colour it should be painted.

Once we’ve finished setting up the archive, we hope to share it with visitors through open days. I’m looking forward to showing people around the lab and sharing some of the stories the paint samples can reveal.

This work was supported by the Arts and Humanities Research Council (AHRC), part of UK Research and Innovation (UKRI), through the Research Infrastructure for Conservation and Heritage Science (RICHeS) programme.