Unreadable – until now (Image: Peter and Nejma Beard/Eurekavision) (Image: Peter and Nejma Beard/Eurekavision)

Secrets of David Livingstone‘s experiences and thoughts from Africa are about to be revealed for the first time, thanks to multispectral imaging enhancement.


To date, historians have had to rely on a heavily edited version of the diaries called The Last Journals of David Livingstone, compiled and published a year after Livingstone’s death in 1873 by his friend, Horace Waller, to whom all the letters were addressed. Now, historians will be able to see what Livingstone really said, experienced and thought in his final and doomed quest to find the source of the Nile.

Most of the letters are virtually unreadable since Livingstone had run out of writing paper and reverted to newspaper and pages ripped out from journals and books, which meant scrawling in the margins and all over the existing newsprint or text. In the 140 years since the letters were written, Livingstone’s ink made from local berries has faded or soaked through the paper, obliterating his words. Now, a project is under way to rescue his words from the mush of paper and print.

The imaging technique accentuates the visibility of Livingstone’s ink while simultaneously suppressing the visibility of the underlying print (see picture). It does this by taking 12 separate images of each document, exposing it in turn to 12 different wavelengths of light, from blue ultraviolet, through the visible spectrum to infrared.

Eureka moment

By feeding the stack of 12 superimposed images through image analysis software, algorithms pick out and best highlight the Livingstone text. “We get the 12 images that stack up in an image cube, and you can process this digitally,” says Michael Toth, the programme manager, who has used the same technique to enhance other valuable ancient documents including the Palimpsest revealing Archimedes’s famous “Eureka” theory, parts of the US Declaration of Independence and Abraham Lincoln’s Gettysburg Address condemning slavery.

Different light wavelengths bring out different parts of the text, Toth explains. So Livingstone’s ink disappears under infrared and becomes most distinct under blue.

The group’s first fully deciphered letter, written in 1871 from a remote village in what is now the Democratic Republic of the Congo, has been made public today in the first stage of the project. The aim is to decipher all the letters written between 1870 and early 1871, just months before Livingstone’s famous meeting with New York Herald reporter Henry Morton Stanley.

The letters amount to around 140 sides altogether, and the four sides comprising Livingstone’s Letter from Bambarre, dated 5 February 1871, showcase the potential of the technology. The letter reveals Livingstone’s despair over his failing health, feeling ravaged by heat and tropical diseases, his intense rivalry towards other African explorers, and his well-documented abhorrence of the slave trade.

“The letter is really just a test run for the much larger diary project,” says Adrian Wisnicki of Birkbeck, University of London, the project director guiding the programme in collaboration with the National Library of Scotland in Edinburgh and the David Livingstone Centre in Balantyre. “This takes us back to the original text and Livingstone’s experiences as he went through this key period towards the end of his life.”

Deciphered diary

Toth says that the next stage of the project is already under way, with all 140 diary pages already scanned and ready for deciphering. He expects the complete versions to be available within 18 months or so.

Like the Letter from Bambarre, they will all eventually be made publically available at Livingstone Online, the leading British-based internet resource for Livingstone’s writings.

The project promises to reveal much about Livingstone that Waller’s editing concealed. He presented the explorer as a swashbuckling hero, an anti-slavery campaigner and martyr. The deciphered letter portrays a man in terrible health, wracked by fevers, weak from bleeding haemorrhoids, and virtually stranded at Bambarre by bone-deep wounds in his feet until his “rescue” by Stanley. All of which Livingstone told Waller to conceal from the public with the words “for your eyes only”.

More true to form, he rails in the letter against the trafficking of slaves saying: “It is awful traffic and can be congenial only to the Devil and his angels.”