Multispectral Imaging
Written by Christina
My final project began with a fascination for the wonderful magic that is Multispectral Imaging. Multispectral imaging is an emerging technology that uses monochrome pictures taken in different light wavelengths to reveal information about objects. It's most practical use it to reveal faded text, but has occasionally been used for pigment mapping.
Last year I asked when is the best time during the treatment plan to image and no one had an answer. While the research has focused on safety for the object and advancing the camera hardware and software there has been no research done on best practices. This intrigued me and I started to read and ask more questions.
It was during a lecture on humidification of paper objects that I developed my theory. That after humidification and before washing was the best time to spectral image because there would be additional space within the paper fibers and the light could penetrate deeper into the substrate.
In order to test this I first had to run it by MSI scientists and read everything I could about it. This led to what is affectionately known as my obsessive fan girl phase. I emailed everyone I could get emails for, had coffee with any scientist who would take the time for me and pilgrimaged to Megavision's headquarters.
Once my project had been vetted by a number of experts I approached University College London about partnering with me on the project as they have a wonderful multispectral imaging camera. The conservation department at UCL’s special collections was incredibly supportive and found objects in their collection to test. They also let me use their conservation lab for treatments as a major concern for the project was transport of the objects to the digitisation suite at UCL after every treatment. The conservation lab is just down the hall making it a short walk.
The objects included two incunabula fragments that had been used as paste downs and a third mould damaged carbon paper letter from the early 20th century. The first two sets were an initial untouched set and a surface cleaned set. Then it came time for humidity day.
The objects were humidified in chambers filled with glycol and water mixtures that held the humidity at 50%, 70%, and 90%. The first object was placed in the 50% chamber and allowed to rest for 1 hour. Then it was imaged and moved to the 70% chamber for a half an hour, then imaged. Moved to the 90% chamber for another half hour, then imaged. Finally the object was left to dry on bondina and blotter before a final image set was taken.
After humidification all objects were repaired and flattened before a final post treatment set were taken. Now my days are filled with image processing and I will have results to share at the MA Symposium this June.
