Scanning device could reveal secrets of historical documents

New technology developed by Oxford University’s classics department could help reveal the secrets of historical documents.

A spin-out firm is commercialising the scanning device, which uses different wavelengths of light to detect faded or erased ink, for analysing manuscripts and archived documents, as well as modern forgeries.

‘The technical leaps we made mean many ancient documents that were previously unreadable can now be scanned and read,’ said Dr Dirk Obbink, head of the research group that developed the scanner.

‘We can set the equipment to interrogate a feature we are interested in: the surface structure, fibres, stains, watermarks, fingerprints, or alterations.

‘We can detect an artist or writer’s signature under multiple layers of paint or the pencil sketch under a watercolour.’

It could also be used to analyse altered or counterfeit documents such as forged passports, bank notes or forensic evidence.

The flat-bed scanner works by capturing a series of images using different wavelength light sources from infrared to ultraviolet.

A computer program then combines them to emphasise the specific colour light absorbed by the faded ink in order to make it appear more clearly.

The technique was originally developed using a high-resolution camera positioned over a copy stand, said Mike Broderick, chief executive officer of the spin-out Oxford Multi Spectral (OMS).

‘You have to use a camera in a dark room, it’s quite big and quite expensive, and manipulating delicate documents in a dark room is not the easiest thing to do,’ he told The Engineer.

‘Once you close the lid on [the scanner] you trap the document so you keep all the extraneous light away and you maintain perfect registration [alignment].’

OMS is now developing the scanner for commercial launch at the end of the year, using proprietary technology specially fitted with different light sources and mounted in a metal enclosure to make it more robust.

The company has secured an investment of £250,000 from a Chinese investor — Changsha Yaodong Investment Consulting Co — and its UK-based partner RTC Innovations, and received £47,600 from the University Challenge Seed Fund last year for prototyping work.