Sunday 4 July 2010

Thomas Jefferson changes his mind

News emerged over the past few days about hyperspectral imaging being used to confirm that Thomas Jefferson changed a key word in the US Declaration of Independence as he drafted it. It has been suspected for over 60 years that he originally referred to fellow subjects (of George III) but hastily over-wrote it to become fellow citizens. This is in a sentence detailing grievances against King George, although the sentence itself didn't reach the final draft.

A Library of Congress researcher used hyperspectral imaging (imaging the document various times using different narrow bands of light and nearby radiation such as infrared) to investigate Jefferson's rough draft late last year. It is unclear why the news came out now, but it was just before Independence Day weekend. See this web page at the LOC which includes a link to multi-spectral image of the Declaration.

I mention this because one of the things Professor Wood noted in his 1910 paper was the use of different bands of light (in his case specifically infrared, visible and ultraviolet) to investigate documents. Infrared especially has a long history of use for investigating both dubious documents (the euphemism for forgeries and tampering) but also helping archaeologists and art conservationists. As early as 1933 the British Museum was using infrared film to help read and decipher writing on millennia-old Egyptian documents and NASA are even now using infrared hyperspectral imaging to garner more from the famous Dead Sea Scrolls.