Kieran's Creation Space
In Fall 2022, I started a Chemistry Ph.D. Program at Portland State University, where I work in The Regional Laboratory for the Science of Cultural Heritage Conservation. Below you can find projects I have been a part of, in conjunction with museums, librarys, and cultural centers in the Pacific Northwest.
The Chachalu Museum, located in Grand Ronde, Oregon, loaned us four objects to study- three glass containers that have been woven around and one woven pipe. We studied these objects using XRF, 2D and 3D x-ray imaging, and DART-MS and were able to find a couple tidbits of information about the objects.
The museum noted that they thought there was metal inside the pipe, which was confirmed through 2D X-Ray imaging. I was not expecting the metal to run through the whole pipe as we saw, but it makes sense, as it was probably used as a support for weaving the pipe.
If you look closely in both images, you can see the metal protruding from the bowl of the pipe. We were able to XRF on this exposed bit to see the atomic makeup of the metal and found that it was mostly iron, which suggests it is a steel of some sort.
An X-Ray image of the pipe. The darker line is the metal running the length of the pipe.
Finally, there is a burnt spot on the back of the pipe and the museum was wonding if we could detect tobacco or other smoking plants on the pipe. This can be done using direct analysis in real time (DART)-MS, which can detect nicotine by seperating out molecules by mass. Through initial checks, tobacco was found on the burnt area, but no other suspected plants were identified.
When this basket was analyzed through CT reconstruction, a lovely treat was revealed- the glass had a ring of trees embossed into it! This was a really cool thing to find, and we have not been able to find anything like it to help us date it or learn more information about its production. However due to the fact that it is threaded and has a seam, it was most like produced post-1920.
Throughout most of the early 1800's, arsenic was a key ingredient in two green pigments: Scheele's Green and Emerald Green. Scheele's Green was commonly used in wallpaper and paints, and even some childrens toys. Emerald Green was used as a paint and a fabric colorant, but also as an insecticide (and yet thought it was fine for humans...?). Of course, arsenic is toxic to humans in very low concentrations, so these pigments were phased out by the late 19th century.
These pigments were also used in book bindings, and more likely than not, on a book in a library near you (panic! well maybe not that but). So The University of Washington Library had some books (50) that they wanted to test for arsenic. In total, we found that 9 of them contained arsenic using X-Ray Fluoresence, most likely in the form of Scheele's Green or Emerald Green. They can be differentiated using Raman analysis, which we plan to do soon.
If you are wondering if a book you have uses an arsenic green, they were usually produced between 1830 and 1870, and are highly decorated with gold titling or detailing. The arsenic green looks like the book shown below (along with its XRF spectrum). To learn more, check out the Poison Book Project.