News from the Conservation Lab — Pretty in Pink

By Caroline Roberts, Conservator

I’ve been spending a lot of quality time in collections storage lately and have noticed something curious: an abundance of pink! Namely, ancient pink pigment. Why is this so interesting? Because the pink most frequently used in the ancient Mediterranean was made of madder root, a plant-based dye that was used to color textiles as well as a pigment on objects.

Like other organic pigments, rose madder is highly light sensitive and prone to fading. The occurrence of rose madder on so many artifacts in the collection surprises me, given what we know about its fugitive nature. Rose madder also has a unique chemical property that causes it to luminesce, or glow, an orange-pink color when exposed to ultraviolet light. A quick look with a UV LED flashlight can help confirm whether or not the pink on an object is madder.

small terracotta hand and arm

Marble sculpture fragment KM 1931.441 from Seleucia with pink pigment between fingers and inside elbow.

sculpture fragment under two different kinds of light
Visible and ultraviolet-induced luminescence (UVL) images of KM 1931.441 showing orange-pink luminescence of rose madder.

Despite its tendency to fade, I am finding pink on everything from terracotta figurines to marble sculpture to limestone grave markers. I’m also finding it in different hues and on different decorative elements, from flesh tones to jewelry to architecture.  It turns out pink is everywhere at the Kelsey, and it is pretty fascinating.

small headless terracotta statuette with pink painted necklace
Marble sculpture fragment KM 1931.15 from Seleucia with pink-colored necklace.
stone with pink pigment
Remnants of pink paint on the surface of KM 21107, a limestone funerary stela from Terenouthis.

December News from the Conservation Lab — X-Rays and Electron Beams!

By Caroline Roberts, Conservator

As an archaeological conservator I know that, sometimes, you need to travel to where the work is. This was on my mind last month when I found myself flying back and forth across central campus, between our lab at the Kelsey Museum and the Electron Microbeam Analysis Laboratory (or EMAL). EMAL is a shared access research space within the Earth and Environmental Science Department, and it’s home to a range of instruments used for materials analysis.

I had a clear mission: to identify the composition of modern architectural limes and mortars from Sudan. Suzanne acquired the samples during the 2019 El-Kurru field season, with the goal of determining whether they were safe for use in architectural conservation at the two Sudanese archaeological sites where a Kelsey team is working.

I used x-ray diffraction and scanning electron microscopy to identify the unknown materials, processes that involve careful sample preparation, instrument setup, and data interpretation. It was time well spent since we now know that some of these materials contain gypsum, which poses risks to archaeological stone. This kind of information is crucial for informed conservation decision-making in the field, and will help shape architectural treatment and preservation plans for the El-Kurru and Gebel Barkal heritage sites.

A large machine
Samples loaded into the Rigaku x-ray diffractometer.
Woman standing next to and looking into a large machine
Not-so-patiently awaiting XRD results!

November News from the Conservation Lab — stone survey discoveries!

By Caroline Roberts, Conservator

 The stone condition survey is well underway, and I am just floored by the richness and variety of the Kelsey’s stone collection. We’ve got limestone that is packed full of shell fossils (fig. 1), alabaster that has weathered in a way that it looks like a sea sponge … and, best of all, so much of the material comes from sites that were excavated by the University of Michigan. If I had to choose the most exciting artifacts I’ve encountered so far, it would be those from Karanis, Seleucia, and Terenouthis. I’m a self-professed ancient color geek, and an incredible number of these objects still have pigment preserved.

limestone with fossils
Figure 1. Shell fossils visible along the side of KM 29001, a limestone funerary stela from Terenouthis, Egypt, late 2nd–early 4th century CE.

Take the Karanis stone. I’ve seen hefty jar bases that have traces of pigment and ground still in place, and a libation altar decorated with a vivid orange-red pigment (red lead?) barely visible under a thick layer of burial dirt. At least half of the Seleucia sculptures I’ve examined have traces of pink pigment, including one with a highly detailed painted necklace. I’ve spent years studying the Terenouthis funerary stelae, and even these continue to surprise me. I spotted blue-green pigment on a well-preserved stela that I am eager to investigate further (fig. 2).

carved funerary stela
Figure 2. Limestone funerary stela from Terenouthis, Egypt, late 2nd–early 4th century CE. Traces of green pigment can be seen in the figure’s left hand and on the recliner cushion. KM 21159.

In addition to revealing the extent of surface decoration on the Kelsey’s collection of stone, the survey is also helping me determine which artifacts are in need of treatment or rehousing. It’s amazing to me how much there is to learn from objects in the collection even now, in some cases nearly ninety years after their discovery.

News from the Conservation Lab — Class is in session!

By Caroline Roberts, Conservator

 I love the start of the academic year, and much of my day-to-day work in the fall is focused on prepping objects for classes. As part of our mission as a teaching and research institution, we offer students a high level of access to the Kelsey collection, and a number of university classes visit the Kelsey each semester. Some of these classes opt in to an object handling session, where students can pick up and examine accessioned artifacts.

teaching-collection
Objects from the Kelsey’s teaching collection on deck for training.

Part of my job is to make sure objects are stable enough for students to handle, and to train new staff and graduate students in how to safely handle objects themselves. I take particular joy in demoing how NOT to do something — nonchalantly waving around a modern kylix from our teaching collection by his broken handle, for example. Another part of my job is to examine and, if needed, treat objects that have been selected for handling by a class. Right now I’m looking at coins for a class focused on visual culture from the ancient Middle East. They are fascinating. Some were minted locally in Syria and Parthia, while others are made from bronze alloys I haven’t encountered before, such as orichalcum. I learn something new each time I look at objects for a new class, and it’s fulfilling to know that the students will, too.

roman coin
Sestertius with laureate and cuirassed bust of Elagabalus (emperor of Rome from 218 to 222), minted in Rome, AD 220. Possibly orichalcum. KM 1991.2.683.

News from the Conservation Lab — August 2019

By Suzanne Davis, Curator of Conservation and Co-Curator of Graffiti as Devotion along the Nile: El-Kurru, Sudan

Friends, we’ve got big news at the Kelsey — a large portion of the river Nile has come to our special exhibition gallery. It’s been re-created by our amazing exhibition team, Scott Meier and Eric Campbell, as have a bunch of life-size columns modeled after those found in the El-Kurru funerary temple. It’s all happening as we finish the final touches on our next special exhibiton, Graffiti as Devotion along the Nile, just in time for the opening on August 23.

empty museum gallery
View of the Kelsey’s special exhibition gallery as installation of Graffiti as Devotion along the Nile progresses. Note the Nile meandering through the right foreground.

This photo shows the relative calm before the storm, since beautiful photographic panels and all kinds of other stuff — including a representation of the ram-headed Kushite god Amun — are going in soon. Although Amun is associated with the sun and with creation, he seems intense and kind of scary and I’m not sure I would enjoy meeting him in person. That said, I think he’s going to look great in our gallery. If you can’t visit in person, check back on our website soon because the online version of the exhibition, built by web guru Julia Falkovitch-Khain, will go live as the in-gallery version opens.

My exhibition co-curator Geoff and I are also really looking forward to our graffiti symposium, which will be held here at the Kelsey on September 20. Yesterday we met with the symposium respondent, artist Jim Cogswell, for a fascinating preview of his thoughts.

And of course, we hope to see you on September 5 at our kick-off event at the Trotter Multicultural Center, where Geoff and I will give attendees a behind-the-scenes look at the El-Kurru graffiti project.

News from the Conservation Lab — Stone Survey!

By Caroline Roberts, Conservator

This summer I’m embarking on a condition survey of the Kelsey’s stone collection, a big project both in scope and in terms of artifact size. As I mentioned in our latest Ugly Object post (ancient earplugs!) the Kelsey’s stone collection is wide-ranging, including everything from tiny steatite scarabs to massive column drums the size of tree trunks. My survey will focus on the larger-scale artifacts and will include vessels, sculpture, and architectural elements made of stone. My goals are to identify which of these artifacts are most in need of conservation intervention, and in the process learn what I can about past stone conservation treatments.

woman with clipboard
Carrie examines stone artifacts in the Kelsey’s collections storage.

The project is a continuation of previous condition surveys conducted by Suzanne Davis, Claudia Chemello, and LeeAnn Barnes Gordon. Their work serves as a valuable baseline for how the Kelsey’s stone artifacts might have changed over the past ten years. Gordon’s research also revealed information about how newly excavated stone was treated at the Roman-Egyptian site of Terenouthis. In the early twentieth century, archaeological chemist Alfred Lucas introduced polymeric materials to archaeologists’ conservation toolkit. Among these was Duco cement, a cellulose nitrate adhesive that was applied to many of the stelae discovered at Terenouthis in order to prevent rapid surface deterioration following excavation. The Duco coating has, however, started to deteriorate, compromising the very surfaces it was meant to protect. Information about historic conservation treatments, along with new condition rankings, will help me develop preservation and treatment plans for the most at-risk stone artifacts at the Kelsey.

stone stela in situ.
Limestone stela during excavation at Terenouthis, Egypt. Kelsey Museum Photo Caption Database.

News from the Conservation Lab — June 2019

By Suzanne Davis, Curator of Conservation

Most of the students and faculty have vacated Ann Arbor for the summer break, but it’s always busy here in the Kelsey’s conservation lab! This month we’re hard at work on all kinds of things.

My main work this month is to finish a book and an exhibition with my colleague Geoff Emberling. Focused on ancient graffiti at the site where we work in Sudan (El-Kurru), these projects have been fun. We’ve learned a lot by working on the book, and the exhibition has been an interesting exercise in how to share the story of El-Kurru and its graffiti with people who will probably never travel there.

Many exhibitions can display objects from a far-away archaeological site to tell a story, but in our case, we can’t transport the El-Kurru pyramid and funerary temple to Ann Arbor (although we can try to fake it). So it’s been a big challenge not only for us but for Scott Meier and Eric Campbell, our Kelsey colleagues who are responsible for the exhibition design, installation, and graphics.

man at computer
Kelsey assistant exhibition designer Eric Campbell enhancing a photo of a graffito from El-Kurru for inclusion in the upcoming exhibition.