A medieval wall painting at the Tower of London has received some special attention from scientists at Nottingham Trent University. Dr Haida Liang and her team of researchers were invited by Historic Royal Palaces to use hi-tech equipment developed at the University to examine the 14th century Byward Tower wall painting – without the need to touch or damage it in any way.
For the past six years, Dr Liang and her team have been refining the development and use of non-invasive techniques for examining paintings and archaeological artefacts.
One tool at their disposal is a portable Optical Coherence Tomographer (OCT), which allows them to scan the surface and the layers below the surface of an object with infrared light. OCT was originally developed as a medical imaging tool, but by using it to examine paintings, Dr Liang’s team realised that they could reveal details not visible to the naked eye. The depth and distribution of paint and varnish layers, and even an artist’s preparatory drawings can all become clear. These details might often only be discovered through the removal of tiny samples from the painting, something that art curators and conservators would prefer to not have to do.
At the Tower of London, the team also made use of a portable remote multispectral imaging system developed in their laboratories at the university. The system known as PRISMS – Portable Remote Imaging System for Multispectral Scanning – allows them to view areas of the painting using different wavelengths of light. In doing so, they can reveal the composition and make-up of the paints that were used, as well as hidden details that might not be immediately visible on the surface.
Jane Spooner, building curator at the Tower of London, has been carrying out detailed research into the Byward Tower wall painting, and invited Dr Liang and her team to help carry out the examinations earlier this year. She said, “Non-invasive examination techniques such as these are invaluable resources in helping us to better understand an artefact like this. We’re able to learn a great deal about what was involved in creating it, and how we can better take care of it for the future.”
Dr Liang added, “This is the first wall painting that we’ve ever examined using these techniques and it’s a real privilege to be asked to work here with such a beautiful and historically significant artefact.”
The Byward Tower wall painting is located on the first floor of the Byward Tower, and because of its fragile condition, not usually open to the public. The painting, which is believed to be added in the 1390s, depicts the the death of Jesus Christ on the Cross, but the central ‘Crucifixion’ figure is gone now – destroyed by a later fireplace. Still surviving though are the Virgin Mary and St John the Evangelist in mourning positions – Mary is wringing her hands with grief for her son and young St John is praying. Either side of the Crucifixion scene are two large saints – St John the Baptist on one side, and the Archangel St Michael on the other.
“This is an incredibly rare Medieval wall painting of extremely high quality,” Jane Spooner told Culture24. “It’s such an important work of art, of national and international significance, so it’s important for us to know as much about it as possible to be able to preserve it.”