Conservators-in-training

For over 10 years, our museum has organized an “Anthropologists in the Making” Summer Camp, and today we hosted 66 of these summer campers in the Artifact Lab for an afternoon of conservation training.

IALSummerCamp1This year the camp is being held over 8 weeks, with different themes each week, including Can you Dig it?, all about archaeology, and Visions and Dreams, which explores the significance of dreams and the roles of shamans and mystics (this one is coming up in August).

The camp theme this week is Mummies Unwrapped so of course we had to give the campers a taste (but not literally) of mummy conservation, in addition to what they are learning about mummies and ancient Egypt.

We organized 3 different activities for the 7-13 year olds (they were split into 2 groups according to age) to test their hand and observation skills. All 3 activities were created to mimic some of the work that we’ve been doing in the Artifact Lab, including:

- an excavation station, which challenged the campers to pick out the remains of a beaded shroud from a bin of mummy debris (similar to recovering PUM I’s beads)

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- a cleaning station, where campers tried different cleaning tests to remove dirt from a painted ceramic tile (like the cleaning that we’ve been doing on our painted coffin of Tawahibre)

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- a materials ID station, where the campers had the opportunity to examine “mystery” materials under magnification and then had to identify what they were looking at (an example of one of the material ID challenges we’ve encountered in the lab can be found here)

A camper compares reference materials to the magnified image of the "mystery" material on the monitor

A camper compares reference materials to the magnified image of the “mystery” material on the monitor

For each activity, we had the kids fill out worksheets to record their observations, to give them a sense of the documentation involved in our work. Before moving on to the next station, each camper needed to get their supervising conservator to sign off on their worksheet. On their way out the door, all campers received certificates declaring them “Junior Conservators for-the-day”.

certificateWe had lots of fun, not only preparing for the camp

Arts and crafts day in the Artifact Lab (left) and the painted tiles before "dirtying" them for the campers (right)

Arts and crafts day in the Artifact Lab (left) and the painted tiles before “dirtying” them for the campers (right)

but also working with the kids at each of the stations. We were impressed with their observations and how quickly they picked up on each activity (rolling swabs can be hard at first!). Special thanks to our Education Department and to all of the summer campers for increasing our department more than tenfold for the afternoon!

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Polarized Light Microscopy

Our Conservation Department recently purchased a Zeiss polarized light microscope-”the best microscope on campus” according to the specialist who set it up for us, and who is knowledgeable about the other scopes in use at Penn. Having the nicest equipment around isn’t familiar territory for conservation labs, so we’re enjoying having this status, but more importantly, having such a nice piece of equipment to use.

Our new microscope installed in the Artifact Lab

Polarized light microscopy (PLM) is used for examination of specimens in many types of laboratories, including biology and geology labs. In conservation, we use PLM for identification of minute fragments from objects-anything from pigment particles to wood fragments to textile fibers. We also use this technique to examine corrosion products, salts, and other materials found on artifacts-all of this work helps us better understand what the objects are made of, their condition, and ultimately provides important information for making conservation treatment decisions.

For example, our Conservation Fellow Tessa de Alarcon, who is conducting a year-long condition survey of Penn Museum artifacts from Kourion, Cyprus, has been using PLM to examine salts present in ceramic vessels from this collection. Tessa is desalinating the ceramics to remove the salts, which likely accumulated in the ceramics in the burial environment and will cause damage if not removed. To confirm which salts are present, she removed samples of the salts and examined them under the microscope. Here is an image of one of the salt samples, which shows that there are 2 different types of salts present-nitrates and sulfates.

Magnified image of 2 types of salts present on a ceramic vessel from Kourion (400X magnification).

You can read more about Tessa’s work with the Kourion collection (and view a cool video clip!) here on the Penn Museum blog.

In the Artifact Lab, one of the first ways that I’ve used our new microscope is to examine fibers from a thread that detached from the fabric wrappings of the falcon mummy I described in a previous blogpost. Fortunately for me (but unfortunately for the poor falcon mummy!) there are lots of detached threads that were available to sample for examination under the microscope. Here is a magnified image of one of these threads:

A small detached thread from the falcon mummy’s wrappings (40X magnification). I noted that the thread has an “S” twist and the fibers are shiny.

Using our binocular microscope, I put a drop of water on the thread and teased out several individual fibers from the thread on a glass slide, and then covered the fibers with a cover slip.

This image shows all of the tiny fibers from the larger thread-it is important to examine these fibers individually in order to identify what type of textile the falcon mummy is wrapped in (40X magnification).

Once the slide was prepared, I mounted it on the polarized light microscope and examined it at 50, 100 and 200X magnification.

Fiber from falcon mummy textile wrappings (200X magnification)

Under such powerful magnification, it is possible to see features such as a very small lumen (central cavity) and nodes along the length of the fiber. These features are characteristic of flax fibers, and comparing my sample with known references (including in this great Fiber Reference Image Library), it was immediately clear that this is what it is. Flax is used to make linen, and since the majority of ancient Egyptian textiles are linen, I already had a good idea that this is what was used to make the falcon mummy-but this proves it!

You can see from this work that PLM is a very useful technique, but it also is important to have an idea about what the possibilities are for what your sample-background research and close examination before microscopy is essential.