Spectral Imaging @CHICC

CLICK for animated gif showing the sequence of the light panels across the spectrum. from UV, through visible to infrared.

Recently at CHICC we have finally begun our tests with our new MegaVision spectral lighting panels. Micheal Toth who has worked on the spectral imaging of the Archimedes palimpsest and other cultural imaging projects joined us for a 2 day workshop. Michael also gave a great presentation to staff about his recent work on the Galen Palimpsest digitisation project, and the importance of creating an online repository for the data. Michael has also been working on an incredible spectral project within St Catherine’s Monastery in the Sinai desert, a wonderful in depth article can be found here.

The light panels work through the electromagnetic spectrum, emitting light from 12 different wavelengths, starting off in UV and working through visible into infrared. We removed the IR filter from our Phase One P45+ back to be able to pick up the invisible light. By photographing objects under this lighting system, we are able to see what is essentially hidden, either text under text, water marks, text on pasted down pages and text obscured by damage.

The 12 wavelengths captured; 365nm UV, 455nm Royal Blue, 470nm, Long Blue, 505nm Cyan,535nm Green, 570nm Amber, 625nm Red700nm IR,735nm IR, 780nm IR, 870nm IR, 940nm IR. This is a Coptic palimpsest fragment, which also has burn damage. Even without processing with ImageJ, we are getting visible results.

The 12 images captured  are then processed through open source software ImageJ. This is the more difficult part of the process. The software is incredibly powerful, but it takes time to process the images and create results. We are currently working with image scientist Bill Christens-Barry in the US who will guide us through imageJ, and work on the images we have collected so far.

We tested the system on a variety of different objects from our collections, to test how the lights can help us with different problems. The famous St. Christopher woodcut, to try and bring out the watermark on the pasted down page. The above Coptic Palimpsest fragment, inscriptions in the Gutenberg Bible that have faded, and most effective without processing, carbonised Greek papyrus fragments, that are barely legible, completely when photographed under normal conditions. The below image shows the difference between normal and infrared. Even without processing the images through ImageJ, you can see the text is now clear.

Carbonised Greek Fragment 222 folio 2.

We will be sending our captured images over to Bill who will guide us through the processing. We will have some more conclusive results soon.

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6 thoughts on “Spectral Imaging @CHICC

  1. […] The Centre for Heritage Imaging and Collection Care (CHICC) of the John Rylands Library has experimented recently spectral imaging technologies on some papyri and other manuscripts. You can read a report on the experiment and see some images from here. […]

  2. […] over the last 12 months, Historic Maps of Manchester going online, our initial experiments with Spectral Imaging, working with more amazing partners, including Blackpool Illuminations and the National Trust. […]

  3. Michael Gilligan says:

    This is very exciting technology …

    Anyone interested in the underlying principles should enjoy the Lumiere Technology website
    http://www.Lumiere-Technology.com/index.htm

    MichaelG.
    Thursday afternoon reader in the Elsevier Room

  4. This looks amazing!! The different coloured images look like an Andy Warhol artwork 🙂
    Very exciting work – well done, guys

    Danielle

  5. […] further steps to recover the lost text. In this instance, the manuscript has also been imaged using Multispectral Imaging. We now use a Phase One Achromatic IQ260 digital back, iXr camera body and standard lens combined […]

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