Cleaning feathers with lasers: a new challenge for scientists and conservators at the British Museum

Our next blog post for British Science Week 2021 comes from Dr. Moira Bertasa, Research Assistant in Laser Conservation Science in the Department of Scientific Research at the British Museum. She describes new research to find a safe way of cleaning feathers with lasers.

The British Museum collection includes many objects made with bird feathers. This includes featherworks from South America and Oceania, but also more unusual objects such as a Victorian necklace with iridescent heads of humming birds and a Chinese snuff-bottle made with blue kingfisher feathers inlaid in silver (Figure 1). Cleaning feathers can be very difficult. Over time, they become brittle and traditional conservation cleaning methods such as gentle vacuum cleaning, brushing or solvent cleaning are unsuitable as they risk damage to the object.

Figure 1 – Hawaiian feather cape (Oc1944,02.2109), Victorian necklace (1993,0205.1)
and snuff-bottle (1936,0413.78). © The British Museum

In such situations, conservators and scientists join forces to explore new conservation techniques. I am a conservation scientist. In these years, I had the opportunity to explore a broad range of subjects from the study of innovative cleaning methods to remove stubborn stains from the artwork to the preservation of graffiti artworks. Currently, I am working with conservators at the British Museum to investigate the application of lasers to clean feathers. Laser radiation was found (by accident!) to be highly effective at removing black encrustations on marble facades while conducting holographic measurements in Venice in the 1970s. Since then, laser cleaning has become an established conservation method to clean stone and ceramics and it has been used at the British Museum since 2002. (To find out more about the Museum’s experience with laser cleaning, have a look at this short video)

Laser cleaning is a non-contact method, which makes it very useful for fragile artefacts, such as feathers. However, laser radiation can also cause serious damage to objects if the laser parameters are not carefully selected. For instance, at a high fluence (which is the energy of the laser per m2), it makes small holes in feathers, something that the conservators definitely want to avoid! This is why I do not test lasers on feathers from museum objects. Instead, I am currently testing our Er:YAG laser (Erbium-doped Yttrium Aluminium Garnet laser) on pigeon feathers collected during a walk in my local park (Figure 2). This way, I can select the appropriate laser cleaning parameters without worrying about causing damage to museum artefacts. I have just started my research and, in collaboration with conservators, hope to determine an effective and safe laser-cleaning procedure for feathers.

Figure 2 – Laser cleaning on different feathers and close up on a pigeon feather showing the holes (Ø 2mm) caused by the laser beam.

Written by Dr Moira Bertasa – Research Assistant in Laser Conservation Science in the Department of Scientific Research at the British Museum (mbertasa@britishmuseum.org)

Further reading

M. Cooper and J. Larson (1998). Laser Cleaning in Conservation: An Introduction. A Butterworth-Heinemann Title

http://www.restituzioni.com/opere/mantello-cerimoniale-tupinamb/ (in Italian)