Headwall Photonics Blog

Hyperspectral Takes Old Maps Into New Territory

Posted by Christopher Van Veen on Thu, Mar 26, 2015

Late in 2014, Headwall sponsored a successful event at London’s Natural History Museum. The purpose of the gathering was to introduce curators and preservationists to the advantages and capabilities of hyperspectral imaging. Professionals in this field understand that the treasures under their control...paintings, documents, and artifacts...need to be preserved using the most advanced techniques available. Preservation largely means having an excellent understanding of the chemical composition of the underlying materials used to create the treasures. And what the eye cannot see, hyperspectral imaging can.

The Bodleian Library (Oxford, UK) has been an acknowledged pioneer with respect to the use of spectral imaging technology. While newer than other imaging techniques, hyperspectral is relatively affordable and provides a wealth of image data that experts can pore through. With this data, the overall body of knowledge is exponentially increased on treasures having enormous historical prestige and significance. The identification of specific materials, inks, pigments, and substrates can help determine when (and perhaps even where) a document or artifact was created. Everything a hyperspectral sensor sees can be categorized with respect to its chemical signature, or ‘fingerprint.’ The color ‘Yellow’ resonates a certain way to the eye, but spectral imaging can discern the chemical composition of a particular ‘Yellow’ and match it to known spectral libraries. The results are clearly beneficial to the Bodleian, which is why the Library has taken great measure to partner with Headwall Photonics to implement systems geared specifically to what they'd like to see and learn.

BodleianTwo prized maps at The Bodleian...the 17th-Century Selden Map of China, and the medieval Gough Map of Britain...recently underwent precise analysis using Headwall’s hyperspectral sensor. The Gough Map in particular represents a mystery to Bodleian experts: when was it created, by whom, and why. By illuminating the map with non-invasive, non-destructive ‘cold’ lighting, the near infrared and shortwave infrared sensors collect a digital map of inks and materials. It even highlights features that were deliberately masked and others that simply faded or flaked away over time.

The Bodleian’s David Howell, an early advocate of spectral/chemical imaging and who helped spearhead Headwall’s Natural History Museum event, has been extremely pleased at the results seen thus far. In an interview with the BBC, Howell said that he was “blown away by the data that’s already coming out.” He noted that the technology first and foremost does not put the treasures at risk. The imaging illumination is non-destructive and the treasures themselves do not need to be removed from their climate-controlled premises.

Howell concluded with a plug for the promise of hyperspectral imaging technology: “Our biggest problem now is there’s just so much data to sort through to fully explore what we’ve uncovered!”

To read the BBC article on this exciting venture, click here.

Tags: hyperspectral imaging, artifacts, antiquities, Artwork, artwork preservation