Conserving a dog skull

BY MADELEINE NEIMAN, 2014–2015 Samuel H. Kress conservation fellow at the Kelsey Museum

This past Friday marked the opening of our new exhibition at the Kelsey: Death Dogs: The Jackal Gods of Ancient Egypt. My favorite object in the exhibition is a desiccated dog skull excavated from Karanis, a Roman-period village in Egypt. Here at the conservation lab we have affectionately named the skull Kalbi, or “my dog” in Arabic.

While he is not the prettiest specimen, the conservator in me is amazed by Kalbi’s phenomenal state of preservation. Large portions of the dog’s skin were preserved by the arid desert environment at Karanis. Even his eyelids and nose remain! Today, I thought I would share with you the challenges of displaying Kalbi, as well as how we overcame those challenges.

Challenge 1: The dried skin covering the skull is extremely fragile. Skin is composed of a network of collagen fibers — chains of amino acids that are spiraled together to form fibrils that, in turn, bundle together to form fibers. As the skin covering the skull dried, the fibers shrank and stuck together, causing it to become brittle and cracked. In several locations along the edges, the delicate skin was in danger of completely falling off.

Solution 1: Cracks in the skin were stabilized by gluing small pieces of Japanese tissue beneath the cracks. The tissue acts like a splint; it bridges/reinforces splits in the skin and secures loose pieces in place.

DSC_4478
Gluing Japanese tissue mends under cracks in the skin.

Challenge 2: Several of the teeth had fallen out of the dental aveoli — the small voids in the jaw that hold the roots of the teeth. While we could easily secure the teeth in place with a small amount of adhesive, figuring out their correct anatomical location was trickier.

Solution 2: For assistance, we turned to Richard Redding, a Kelsey Research Scientist and zooarchaeologist (specialist in archaeological faunal remains). Richard determined the proper placement of each tooth, and we glued them into place.

Challenge 3: We needed to find a way to put the head back together. The dog’s head came to the lab in two pieces; without muscles to hold them together, the skull and jaw had separated. Unfortunately, the fragile teeth and delicate skin along the lower jaw meant that the skull could not safely rest on top of the jaw.

Solution 3: A mount. The creation of mounts is typically the domain of our talented exhibition preparator Scott Meier. When objects are particularly fragile, however, Scott and the conservation staff collaborate. In this case, we combined forces to create a mount that would allow the skull to float above the jaw, giving the appearance of a complete head without allowing the two pieces to touch. Scott made a raised support using a carved wood block and brass dowels. To the top of the wood block, I attached carved pieces of ethafoam, which keyed into raised areas along the base of the cranium, locking it into place. With the skull held above, the jaw could be slid into place below. Each piece is separately supported, but Kalbi’s head appears complete.

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Kalbi on display at the Kelsey Museum.

As you can see, the preparation of objects for exhibition is a team effort! We hope you will come by to visit Kalbi and all of the other artifacts on display in Death Dogs: The Jackal Gods of Ancient Egypt.

Conserving a Seleucian Incantation Bowl

BY MADELEINE NEIMAN, 2014–2015 Samuel H. Kress conservation fellow at the Kelsey Museum. During her time here, Madeleine’s work will focus on the technical analysis and treatment of objects from the Seleucia collection.

KM 31455
Incantation bowl (KM 31455) from the site of Seleucia on the Tigris. The object is a wheel-thrown, buff-colored earthenware bowl the surface of which has been painted with black pseudoscript (small lines meant to mimic Aramaic writing) and images of anthropomorphic figures.

The vessel was excavated in the 1930s from Seleucia on the Tigris, a site approximately 18 miles south of modern-day Baghdad, Iraq. Magical bowls like this one were placed in the corners of houses or under thresholds as a means to protect their owners from evil spirits. The text and images drawn served to combat demons or other supernatural beings that might harm the object’s owner. Today incantation bowls, including this one, are important for the study of ancient magical and religious practices.

Can you guess why the bowl came to the conservation lab?

How about if you compare it to another incantation bowl in the Kelsey collection?

KM 33756
Incantation bowl (KM 33756) from the site of Seleucia on the Tigris. The object was found alongside the above-pictured bowl.

Yes. That’s right. There is a thick, dark crust covering much of the interior and exterior of the bowl, and it hides the decoration on the bowl’s surface. Curators here at the Kelsey have asked the conservation lab to remove the crust so that the decoration on the surface is easier to see. Before the crust can be removed, however, conservators must figure out what this strange material is.

Based upon a close examination of the surface, we suspect the crust is most likely one of two things.

Option 1: Salts! This bowl was buried under ground for approximately 2,000 years.  During that time the porous ceramic vessel was likely exposed to groundwater containing a range of salts; chlorides, nitrates, phosphates, and sulfates are all commonly present in soil and are, as a result, often found within the fabric or on the surface of ceramics recovered from archaeological contexts. While salts typically appear as areas of white crystalline efflorescence on an artifact, they may also occur as dark, hard surface accretions similar to the material visible on the bowl.

Option 2: A modern coating. It is possible that the darkened surface is due to the application of a modern coating.  During the 1930s, when this object was excavated, archaeologists and conservators often covered artifacts with a resin or glue in an attempt to protect and strengthen surfaces. While these materials were applied with good intentions, they can alter over time in unexpected and undesirable ways. A once clear, coherent coating could become dark and brittle like the coating on the bowl.

However, as Sir Arthur Conan Doyle notes, “it is a capital mistake to theorize before one has data.” So … how will conservators here at the Kelsey get the data necessary to determine what is covering the bowl?

Like historians, conservators look at archival records. The Seleucia archive at the Kelsey Museum holds a range of primary source documents created by archaeologists at the time of excavation, including journals, object lists, and photographs. We will examine these documents for any clues to what the bowl looked like at the time of excavation (e.g., was the bowl’s surface dark when removed from the ground?) as well as the conservation methods that might have been used on the bowl. We will also utilize a range of scientific examination techniques available across the University of Michigan campus to study the chemical makeup of the crust.

I hope you will check back with us in the coming months as we work to uncover the surface of this bowl.

Using UV light to examine ancient paint

BY MADELEINE NEIMAN, 2014–2015 Samuel H. Kress Conservation Fellow at the Kelsey Museum. During her time here, Madeleine’s work will focus on the technical analysis and treatment of objects from Seleucia on the Tigris, a site approximately 18 miles south of modern-day Baghdad, Iraq.

One of my major projects here at the Kelsey is conducting a survey of artifacts from the Seleucia collection. The goal of this work is to answer three questions:

  • What are the artifacts made of and how are they made?
  • What is the condition of the object? More simply, is there any evidence of damage or deterioration (e.g., breaks, cracks, discoloration) present?
  • Have the objects been modified (e.g., repaired or reused) in any way by modern or ancient people?

Conservators utilize a number of tools to help us answer these questions. Today I thought I would share with you a bit about one of our most commonly employed techniques — examination under ultraviolet light.

Light is a form of electromagnetic radiation and exits as part of a large electromagnetic spectrum. Ultraviolet radiation, often called UV light, refers to that area just below what is visible to the human eye. While we can’t see UV light, when it illuminates the surface of an artifact, certain types of materials, including some dyes, minerals, and resins commonly found on archaeological objects, fluoresce. These materials glow different colors!

Let’s look at an example.

Among the over 13,000 objects in the Seleucia collection are a group of bone figurines.   Several of these are decorated with a reddish-pink paint that displays a unique orangey-pink fluorescence.

Images of bone figurine (16187) with pink paint captured under visible (left) and UV (right) illumination.
Images of bone figurine (KM 16187) with pink paint captured under visible (left) and UV (right) illumination.

In antiquity, people created paints using mineral pigments as well as organic colorants found in plants and animals. Among the most common sources of red were the pigments hematite (iron oxide), cinnabar (mercury sulfide), and red lead as well as the dyes kermes (from the Kermes vermilio insect) and madder (from the plant Rubia tinctorium).  When viewed in visible light all five appear red. However, when examined under UV light, one stands out: madder. Madder contains four principal colorants: alizarin (red), purpurin (red), pseudopurprin (red) and xanthine (yellow). The purpurin and pseudopurpurin glow a bright orangey-pink when exposed to UV light, making it easy to distinguish.

By examining the figurines under UV light we can tell that an ancient artist used madder to decorate these figurines!

News from the Conservation Lab

The Kelsey Conservation Lab is pleased to welcome Madeleine Neiman as our new Samuel H. Kress Fellow for the 2014–2015 academic year.

Madeleine is a recent graduate of the UCLA/Getty Program on the Conservation of Archaeological and Ethnographic Materials, and has an undergraduate degree in anthropology from Bryn Mawr College. She just completed a year-long graduate practicum internship at the Arizona State Museum (University of Arizona) and has also previously worked at the Colonial Williamsburg Foundation, the Alaska State Museum, and the Anchorage Museum, where she focused on the conservation and technical analysis of ethnographic and archaeological materials.

Madeleine Neiman
Madeleine Neiman

At the Kelsey, Madeleine’s research will center on conservation projects for the Seleucia collection. For example, she will research and treat an incantation or “demon” bowl from Seleucia, an unglazed ceramic bowl painted with magical spells designed to entrap demons. The inscriptions on this bowl are obscured by a darkened surface layer (possibly a modern coating) and by the presence of chunky salts, probably deposited while the bowl was buried. Important goals of conservation treatment will be to stabilize the bowl’s inscription and make it more legible.

In addition to the bowl, Madeleine will survey and study a group of bone figurines from Seleucia. The figurines are carved in both stylized and naturalistic human forms, and some are painted. Madeleine will collaborate with zooarchaeologist Dr. Richard Redding, as well as materials scientists at U-M and elsewhere, to answer a variety of research questions about the figurines.

Bone figurine from Seleucia
Bone figurine from Seleucia.

We are thrilled to have Madeleine here to research and treat these unique artifacts, and we’re grateful to the Samuel H. Kress Foundation and the Foundation of the American Institute for Conservation for supporting her fellowship. Welcome, Madeleine!