archaeological conservation – The Kelsey Blog

archaeological conservation

News from the Conservation Lab – April 2023

By Caroline Roberts, Conservator

Hello, friends of the Kelsey Blog! The past six months have really flown by, haven’t they? Suzanne and I have spent quite a bit of this time traveling for work, something that we both missed during the pandemic. Here are some highlights!

In September and October, Suzanne and I returned to Abydos, Egypt, where we provide conservation for the Abydos Middle Cemetery (AMC) Project. We worked on a variety of things, including objects from the serdab of Weni the Elder, as well as newly excavated artifacts, alongside our Egyptian conservator colleagues Hamada Sadek and Ahmed Abdullah. Being back there—and being a part of the Weni project—was such a thrill. 

Single story white structure surrounded by sand and palm trees under a blue cloudless sky with rock formations in the background.
AMC dig house at Abydos, Egypt

In November, Suzanne and I gave papers at the American Society of Overseas Research’s annual meeting in Boston, where Suzanne presented her research on gender equity in museums and I participated in a workshop on Roman-Egyptian funerary portraits. It was great to see colleagues in the flesh once again after many years of virtual meetings and to be able to visit some old stomping grounds, including the Museum of Fine Arts, Boston, where I took in the newly reinstalled Greek and Roman galleries. Check out this truly inspired loom weight display (I love it so much I just had to share it with you folks)! We also enjoyed a tour of the Harvard Art Museums with recent IPCAA graduate Caitlin Clerkin, who works there as a postdoctoral fellow.

Five ceramic loom weights of various sizes and shapes attached to threads in a museum display case.
Ceramic loom weights, Museum of Fine Arts, Boston; Acc. #s 84.381, 84.373, 84.374, 84.370; Greek East, 6th–4th centuries BCE, from Assos (Behramkale, Turkey)

In January, Suzanne traveled to Jebel Barkal, Sudan, where she is directing site preservation with her team of conservators and conservation architects including Elmontaser Dafalla, David Flory, and Sefian Mutwakil. Check out her blog post and more news from Barkal here.

As always, there is a lot going on in the Conservation Lab! Keep tuning in.

Ugly Object of the Month – October 2022

By Caroline Roberts, Conservator

Welcome, dear readers, to Ugly Object of the Month Halloween edition (cue the spooky organ music)! I’ve been sharing a lot of ancient panel paintings with you folks lately, and I hope you’re ready for more…

because this month’s object is, indeed, a painted wood panel from Karanis, Egypt (cue the maniacal laughter)!

KM 28807, wood panel fragment painted with an image of Aphrodite; Karanis, Egypt, 2nd – 4th century CE
KM 28807, wood panel fragment painted with an image of Aphrodite; Karanis, Egypt, 2nd – 4th century CE

Can you make out the (dare I say?) spooky lady emerging from this panel’s aged, discolored paint layer? You may be wondering… who is this mysterious figure? If you can’t tell looking at the object under visible light, take a look at the infrared reflectance image below. The woman is clad in a diaphanous robe, jewels, and a conical crown, all of which suggest that she is a goddess—probably Aphrodite. In Roman Egypt, Aphrodite and Isis were often worshipped as a single deity, and her potency took on aspects of both goddesses: fertility, childbirth, but also rebirth. Which makes this lady more magical than mysterious.

(IRR) image of KM 28807
Infrared reflectance (IRR) image of KM 28807

News from the Conservation Lab—analyzing ancient portraits and panel paintings

By Caroline Roberts, Conservator

Every time I walk through the first-floor galleries I like to pay a visit to KM 26801—the remarkable portrait of a woman on display in the museum’s Egyptian galleries. This arresting painting is a type of funerary object that was popular in Roman Egypt: a painted wooden panel that would have originally been secured via linen wrappings over the face of a mummy. Portraits like this one can be found in collections worldwide. They are often separated from their mummy, with their original findspots unrecorded and now no longer known.

We are taking a closer look at the Kelsey’s collection of panel paintings as part of the conservation lab’s ongoing NEH Color Research project, with the goal of adding what we learn to our growing color dataset, as well as to the APPEAR mummy portrait database. Multispectral imaging has allowed us to reinterpret the imagery of one panel painting (featured in an earlier blog post), and it has allowed us to identify pigments on mummy portraits in the Kelsey collection. On one painting (KM 26574, pictured here), the sitter wears a purple clavus (a decorative strip of fabric worn on the shoulder) that is painted in a way remarkably similar to the purple robe of the woman in KM 26801. On another, Egyptian blue appears in unexpected places in the figure’s skin—something we see in portraits from other collections. We also found another blue pigment—indigo—in the hair of a mummy portrait fragment that was discovered in a house at Karanis.

Fragment of a mummy portrait. Roman Egypt (Minia?), 2nd century CE. gift of Peter Ruthven. KM 26574.

All of this provides us with more evidence about the materials and techniques artists were working with when they painted these wonderful panel paintings and portraits. Just another day in the Kelsey conservation lab!

Ugly Object of the Month — March 2022

By Caroline Roberts, Conservator

This month we are celebrating Women’s History Month with an uncharacteristically handsome Ugly Object: a sestertius coin featuring the indomitable empress Julia Domna.

Bronze sestertius. Septimius Severus for Julia Domna, 193–211 CE. Gift of George Monks, 1991. KM 1991.2.657.

Julia Domna was born in modern-day Syria to a family of Arab priests and became empress of Rome when her husband, Septimius Severus, defeated multiple co-contenders to the imperial throne in 197 CE. Julia Domna was a highly visible and powerful political figure who influenced the reigns of both her husband and her son, Caracalla. Her image appears in a range of marble carvings, in painted wood on the famous Severan Tondo, and countless coins—including KM 1991.2.657. Julia Domna appears on the obverse side of this coin draped with hair coiled and waved, encircled by her honorary title, Julia Domna Augustus. The goddess Juno, accompanied by a peacock, appears standing on the reverse.

These powerful images of women—one historic, one mythical—would have played an important role in amplifying the authority of the emperor by circulating the empire as currency. We don’t know where this coin was found, but I like to imagine it was carried around in the pocket of someone outside Rome—maybe as far afield as Julia Domna’s own hometown?

Attention, Ugly Object devotees! Giving Blueday is Wednesday, March 16!

Announcing 2022’s Giving Blueday, the University of Michigan’s 24-hour celebration of giving. Every March since 2014, the global U-M community has come together on Giving Blueday in support of programs and causes they care most about.

We know that the Kelsey’s Ugly Objects are uppermost in your mind when you consider making charitable donations with your hard-earned money. Any donation you make to the Kelsey Museum on Giving Blueday will support our broadest goals—including the careful conservation of these unique beauties. Gifts to the Kelsey are like the artifacts we care for: even if they seem small or insignificant, we love and appreciate every one.

So mark your calendar and give a dollar on March 16! Give two dollars! Give five whole smackers in commemoration of the love we know you feel for Franken Horse!

Learn more about what your donation to the Kelsey Museum supports at our website.

News from the Conservation Lab — Exploring bronze corrosion under the microscope

Harrison Biggs at the microscope.

This month we’re excited to welcome Harrison Biggs as our Conservation guest-blogger! Harrison is interning in the Conservation lab as part of the Museum Studies Undergraduate Program.

By Harrison Biggs, Conservation Intern

This semester I’ve been given the opportunity to work with Carrie and Suzanne as an intern here in the Kelsey Conservation lab. As an intern, I’ve been doing a lot of multispectral imaging and XRF analysis for the ongoing NEH Color Research project, but the project I’ve been most excited about lately is the treatment of this little bronze statuette (KM 3090).

Bronze Isis and Eros figurine. Graeco-Roman Egypt. Purchased from David Askren, 1925. KM 3090.

Even though treatment in this case just means picking harmful materials off the object with a pin (it’s more fun than it sounds), this has been a great opportunity to learn about the ways that bronze objects age. Bronze corrosion is an incredibly complex process where even small environmental changes can lead to the generation of drastically different minerals and patterns, but there are a few minerals that appear more than others.

Cuprite (Cu2O), a red-orange-brown copper oxide, and Malachite (CuCO3-Cu(OH)2), a pale green copper carbonate, are fairly common corrosion products that often form protective patinas on ancient bronze objects. Azurite (2 CuCO3-Cu(OH)2) is a less stable copper carbonate that tends to manifest as small blue crystals on an object’s surface. Nantokite (CuCl) is a soft, waxy copper chloride that forms commonly under burial conditions. When it gets too moist, Nantokite transforms into powdery, light green Paratacamite (Cu2(OH)3Cl), commonly referred to as “bronze disease.” Paratacamite is the main target of the treatment because, if allowed to spread, it can reduce an object to powder.

Together with a pile of less common and similarly colored minerals, these form a beautiful little world that I have the privilege of staring at through a microscope for hours at a time. I hope you enjoy looking at it as much as I do!

The surface of the figurine under 10x magnification.

News from the Conservation Lab — November 2021

By Suzanne Davis

Hello, readers! As always it’s a busy time in the Kelsey Conservation lab, and we are feeling excited about our winter work. Since we often focus on cool objects in this blog, I thought I would give you a little peek into all the other stuff we do, and I’m going to illustrate this with a photo of my messy desk / lab bench.

color photo of a desk strewn with papers and an open laptop. A gavel rests on top of a short stack of books.

At left there are samples of (modern) building materials we’ve been testing for use at the Jebel Barkal and El-Kurru archaeological sites in Sudan. Next, half-buried under other things, is a copy of the budget my colleague Geoff Emberling and I are working on for those two archaeological projects—we hope to be in the field in Sudan this winter.

The pile on top of this is related to board meetings for the American Institute of Conservation (AIC), and the Foundation for Advancement in Conservation (FAIC). As AIC president, I’m responsible for running the AIC board meeting, so I’ve got the presidential gavel (passed down from president to president since the 1980s) and my copy of Robert’s Rules of Order, the Classic Manual for Parliamentary Procedure (ditto). Tucked underneath this are my notes from those meetings, including a quote from my FAIC board colleague and friend, Bob Mitchell, who runs a successful consulting firm that focuses on marketing and strategy. The quote is, “What got you here, won’t get you there.” Bob believes it’s important to have a spirit that embraces change and re-imagination right now. I like this idea!

Next up is a messy clipboard with a flow chart that I’m consulting for identification of ancient dyes, and this overlays all my notes about the multispectral imaging I’m doing. Finally, on my computer screen is a copy of the schedule for the annual meeting of the professional archaeological association ASOR. It’s happening in Chicago this week, I and many of my Kelsey colleagues are participating in the conference, and we are very excited to attend it in person this year!

Ugly Object of the Month — November 2021

By Caroline Roberts, Conservator

This month’s Ugly Object—a fragmented wood panel painting from Karanis—is a visual challenge. One interpretation I’ve read describes what we’re seeing as hair. But to me, this looks like a figure. Take a look at the infrared (IRR) image I captured—what do you see? I see some kind of furry (or feathery) creature with a pendant hanging around its neck. I think I see a bit of a wing and two bird legs. And I think I see a wreath-like object in front of those feet. Could this perhaps be an eagle with some imperial imagery thrown in? This is my best guess, and I’m sure there are other possibilities. What do you think, readers?

KM 23976, panel painting of a bird (eagle?). Roman Egypt (Karanis), 1st–5th centuries CE. Left: visible light image; right: infrared (IRR) image.

News from the Conservation Lab — It’s Fall, Y’all

By Suzanne Davis

Campus is hopping with students and faculty here in A2, and I have to say—it’s pretty fun. Our Wolverine community is doing great on vaccinations and masking, and the energy from having everyone back together is inspiring. Meanwhile, here in the conservation lab, lots of projects are either continuing or just getting started.

A new(ish) project I’m especially excited about is the Kelsey’s Jebel Barkal Archaeological Project, which is gearing up for a 2022 winter field season in Sudan after being grounded during 2021. We have several generous sponsors for this work, including the Bureau of Educational and Cultural Affairs at the U.S. Department of State, which will be funding conservation work at the site through a large Ambassador’s Fund for Cultural Preservation grant. If you’d like to learn more, please visit our brand new website, which I and several of my colleagues have been developing over the past month. I encourage you to sign up for the Jebel Barkal blog and stay tuned, since we’re working on adding other social media.

If you’re a regular reader of this blog, you’ll know that we luuuuv fall around here. Luckily for us, it’s the autumnal equinox and the weather has turned right on schedule—from 80 degrees and sunny to 60 degrees and raining like crazy. We’re putting on sweaters and re-reading Colin Nissan’s McSweeney’s essay on decorative gourds. I’m not going to link it, because the language is too fruity for a family-friendly blog, but if you already know and love it, now is officially the time to get reacquainted.

Image by Janelle Batkin-Hall.

News from the Conservation Lab — exploring the Kelsey collection with X-rays

By Caroline Roberts, Conservator

Suzanne and I are excited to announce a new addition to our lab: a handheld X-ray fluorescence (XRF) spectrometer. We were able to acquire this instrument with the help of the NEH-sponsored Research and Development grant we received this year. This nifty-looking handheld device—which, to me, resembles something out of an original Star Trek episode—is engineered to generate a powerful X-ray beam. The X-rays are directed onto an object, where they are absorbed by atoms that make up the pigment particles in an ancient paint layer. This initiates a phenomenon called the “photoelectric effect” which results in a release of photons from the atom. These photons have quantifiable energy levels that are unique to specific chemical elements, such as iron, copper, lead, mercury, or arsenic. The XRF device can detect these photons as they leave the object, and convert this information into a graph that we can read. All of this can be done without removing a paint sample from the artifact.

XRF machine being used in a lab
Bruker Tracer 5g handheld XRF spectrometer positioned on a tripod over KM 21114, a limestone funerary stela from Terenouthis, Egypt, late 2nd–early 4th century CE.

We’ll use the XRF unit, along with our lab’s multispectral imaging kit and polarized light microscope, to identify pigments that were used on artifacts at the Kelsey, providing us with materials-based evidence of what artists were using to decorate objects and structures in the ancient world. For the NEH grant, we’ll be focusing our investigative efforts on the collections we have from Karanis and Terenouthis. We’re especially interested in learning which pigments people were using to paint artifacts in Roman Egypt, since there isn’t as much data from this later period as there is from earlier parts of Egypt’s history.

News from the Conservation Lab — March 2021

By Suzanne Davis

Hello! Happy end of winter! This week in the conservation lab we’re pretty excited about two things. First, we just had a research study be published in the journal Studies in Conservation. Written with our colleague Andy Poli, in U-M’s Department of Mechanical Engineering, the paper examines the behavior of conservation adhesives in hot climates and focuses on an adhesive that we tested extensively at the hot field site of El-Kurru, Sudan. The article is titled “Paraloid® B-72/B-48N 1:1 as an Adhesive for Use in Hot Climates: Literature Review, Laboratory Testing, and Observational Field Study.” It’s about glue, basically, and it involves molecular and physical chemistry, making it a topic that is both boring and complicated to understand. BUT we worked hard to make the writing clear, accessible, and active. The reviewers seemed to appreciate this, and we hope other archaeological conservators will find this study useful for their work.

broken pot in a basket
A large pottery jar at El-Kurru, Sudan, in 2016 after our usual conservation adhesive failed due to high heat. Failure like this is why we started researching adhesives for use in hot climates.

Second, this month we’re beginning work in earnest on our new, NEH–funded study of color in the Kelsey’s collections, and I’ve been selecting textiles to examine. We’re still early in this project, and I’m struggling with how to choose fragments for analysis: Pretty colors? Interesting fabric constructions? Good archaeological context?  So far I’ve got some of all the above, although the latter is complicated by how the excavators at Karanis, Egypt, understood and recorded stratigraphy in the 1920s. Still, it’s a lot of fun, and we look forward to new discoveries.

textile fragments
A selection of textiles—all from Karanis, Egypt—for the just-beginning technical study of color in the Kelsey’s collections.

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