Preserving iconic Japanese art

The 19^th century woodblock prints, by the artist Hokusai, were traditionally made using plant-based pigments, which can fade when exposed to light. But the extent that this might happen was unclear, as the particular colorants used in the prints had never been scientifically analysed. Before putting them on public display, curators at the museum wanted to be sure they wouldn’t suffer damage.

Bradford PhD student, Peter McElhinney worked with Capucine Korenberg, a conservation scientist at the British Museum, to analyse the pigments in two of the most well-known prints included in the exhibition: ‘The Great Wave’ and ‘Red Fuji’. Using X-ray fluorescence, they were able to identify which elements were used to produce the colorants, while a further technique, called multispectral imaging, enabled them to identify the particular pigments used based on how they reflect different kinds of light.

“Bradford has real strengths in the area of analytical science, and it was a privilege to get the opportunity to work with some of the UK’s leading heritage scientists on these beautiful prints,” said Peter. “The analyses have told us a lot about how the prints were produced and how to best preserve their colours while they are on display”

The prints also underwent microfading tests, in which a tiny spot of bright light is focused on an area of the print and any fading in the ink is measured using a spectrometer – an instrument that is very sensitive to colour changes.

Dr Korenberg said: “Microfading tests help to mitigate the risk to objects in the Museum’s collection enabling recommendations to be made to assess the length of time light-sensitive objects can be displayed, as well as on the intensity of light in the gallery.”

Based on their findings, the researchers were able to advise the museum not to display these prints for more than 20 per cent of the time, and to use only dim light. Following three months of exhibition, the prints should be stored in the dark for at least a year before being displayed again.

Writing in a blog about the work, Dr Korenberg explained: “While these measures will not stop fading from occurring altogether, they will ensure that these world-famous prints fade so slowly that they will be seen by countless generations of visitors to the Museum in the future.”

Peter’s placement was funded by the Heritage Consortium, through a grant designed to develop knowledge and experience within the heritage sector. The Exhibition, called Hokusai: Beyond the Great Wave, is on display at the British Museum until 13 August 2017.

Image: Under the wave off Kanagawa (The Great Wave) from Thirty-six views of Mt Fuji. Colour woodblock, 1831. Acquisition supported by the Art Fund. © The Trustees of the British Museum. On display from 25 May - 13 August.