archaeological conservation – Page 6

The Barosso watercolors are back!

Leave a Comment / Conservation / August 5, 2014

FROM THE KELSEY CONSERVATION LAB

Barosso reinstall_02 — Conservators from ICA Art Conservation prepare to reinstall a watercolor panel.

Barosso reinstall_01 — The Barosso panel being reinstalled.

Following a brief hiatus from display, the Kelsey Museum’s famous renderings of the Villa of the Mysteries fresco cycle are once again on view. Commissioned by Francis Kelsey himself in the mid-1920s, the watercolors were painted by Italian artist and archaeologist Maria Barosso at a scale of 5/6 the size of the original frescoes in Pompeii. The watercolors captured the vivid color of the frescoes before color photography existed. They have served as an important educational tool and document of the paintings’ condition at the time the renderings were created. The original frescoes have darkened significantly since the time of the Barosso commission, and they are currently undergoing laser cleaning by conservators at Pompeii.

The Kelsey was able to put the watercolors on permanent display for the first time in 2008, thanks to the space provided by the new Upjohn Exhibit Wing, and an IMLS grant to support their conservation treatment and installation in the galleries. Conservators at ICA Art Conservation carried out this complex treatment, as well as some recent repair work to the watercolors’ mounting system that required their temporary deinstallation. It took about three days to reinstall the massive panels, the largest of which is 5 x 20 feet.

We are so grateful to conservator Jamye Jamison, Chris Pelrine, and 05 (that’s right, our colleague’s name is zero-five) for all their hard work!

The Barosso watercolors are back! Read More »

News from the Conservation Lab

Leave a Comment / Conservation / June 18, 2014

BY SUZANNE DAVIS, Associate Curator and Head of Conservation

At the end of May, I attended the big professional conference for conservators in the United States — the annual meeting of the American Institute for Conservation. This was a special meeting for me because I was in charge of the program for the “Objects” group. This group has about 900 members, all of whom focus on the conservation of three-dimensional art and artifacts — in other words, objects.

Usually at a conservation conference, I attend the presentations about archaeological conservation because that’s what will help me most in my work for the Kelsey. But this year, because I was the program chair, I had to be there for ALL the papers. I wasn’t sure I’d enjoy it, but it was great!

Conservator Hiroko Kariya at work at Luxor Temple, Egypt. Photo from the University of Chicago/Oriental Institute Epigraphic Survey webpage.

I learned about conservation work at Luxor Temple in Egypt — that’s up my alley — but also about preservation of public art in the Modernist architectural mecca of Columbus, Indiana (who knew?) and about conservation of the Watts Towers in Los Angeles, California, a National Historic Landmark sculptural site created by Sabato Rodia between 1921 and 1954 that’s considered a masterpiece of “outsider art.”

View of the Watts Towers. Photo from the Watts Towers webpage.

I also heard about the National Air and Space Museum’s amazing research and conservation of a Nazi Bat Wing stealth fighter aircraft made out of plywood (you can read a recent post about this work here on the NASM blog) and about preservation of animation cels at the Walt Disney Animation Research Library. I learned about how conservators at the Arizona State Museum are treating pine-pitch–coated Native American baskets, and about how a team at the Field Museum of Natural History in Chicago used CT scanning to virtually restore a skull from the Magdalenian Era.

Magdalenian Era skeleton, with subsequent virtual facial reconstruction. Photo from University of Chicago Radiology webpage. See a Field Museum video about this project, featuring conservator JP Brown, here.

I gained a surprising amount of useful information about the treatment of complex, composite objects from these papers. This is knowledge that I can, actually, apply to my work at the Kelsey. Continuing education rules!

News from the Conservation Lab Read More »

Analyzing an Egyptian Textile Fiber

1 Comment / Conservation / May 12, 2014

BY BRITTANY DOLPH, Graduate Conservation Intern, UCLA/Getty Conservation Program

Here in the conservation lab, we’ve been busily preparing for the upcoming exhibition Ancient/Modern: The Design of Everyday Things. One of the objects in the exhibition is this child’s garment, excavated from the site of Karanis, Egypt, in the 1920s and ’30s. The dry Egyptian desert creates excellent preservation conditions — so much so that even fragile organic materials like this textile can survive for 2,000 years.

Last month, Kate Carras wrote about her favorite textile fragment from Karanis. Her favorite fragment was made differently from the garment shown above, but the materials are the same: wool yarns. You might wonder, how do we know for sure what kind of yarn it is? How do we know that it’s not linen or cotton?

In the case of this garment, there was a meticulous analysis of the weave pattern and yarn structure in the object’s records but no identification of the fibers present. Knowing the fiber type is important for conservators because it helps us make good decisions about how to care for the textile. When we want to identify the fibers that make up a yarn, we carefully take a tiny sample of the fiber to examine with a microscope.

tunic2-3 — (left) Photo-documentation of the blue warp sample location. (right) The labeled sample temporarily mounted on a glass slide with water.

We mount the sample on a glass microscope slide by placing a drop of water over it and a glass coverslip atop the water. The water serves both to improve the optical properties during examination and to hold the fiber in place.

What are we looking for? Different types of fibers have different surface clues, or morphological features, that tell us whether they are wool or hair (from an animal), cotton, linen (from the flax plant), or another type of bast fiber (also from plants). In this case, it looks like the samples are all wool.

(left) Dark blue warp fiber, magnified at 200x. (right) Fiber sampled from a pink weft, also magnified at 200x. The scales suggest that the fibers are both wool.

A beige weft sampled from the proper right sleeve, magnified at 50x, also wool.

The first clues that the fibers are wool are the small, jagged lines (called scales) visible on the surface. The second clue is a feature called the medulla — the central air space that travels the length of the fiber shaft.

In this image, the medulla is faintly visible as a slightly darker column traveling down the center of the fiber (50x).

Though time did not permit us to investigate further, other methods can be used to narrow down the source even further, to a class of animals — for example, goats or camelids.

Identifying the fibers used in a textile contributes to archaeological research, determines what conditions are best for a textile’s preservation, and helps direct future conservation treatments.

Analyzing an Egyptian Textile Fiber Read More »

Conservation for Seleucia Show, Part 3

Leave a Comment / Conservation / April 1, 2014

BY BRITTANY DOLPH, Graduate Conservation Intern, UCLA/Getty Conservation Program

It may come as a surprise that sometimes conservators decide to not treat an object, after consulting with archaeologists and curators. One reason for this might be that the treatment would destroy information that’s important to scholars. This always has to be weighed against the risk that the artifact could fall apart or change irreversibly. An instance in which we might not treat an object would be the case of this figurine that has a black resin or sticky substance on it.

brittanypt3-1 — A ceramic figurine, shown from the rear, showing a thick, black accretion along a break edge.

Though the resin might be considered an eyesore, we did not remove it in case it is actually an ancient repair. In fact, there are references to repair materials and practices in classical sources, one of which is pitch. On the other hand, a more modern mounting material, such as displayed by this figurine, was indeed removed, by placement in a vapor chamber. The solvent vapors penetrated the adhesive attaching the mounting material, allowing for quick and gentle removal.

brittany2-3 — Left: stone head fragment “before treatment” (IL2012.04, TMA 1931.436), to which has been adhered a modern mounting material. Right: “after treatment” shot, in which the mounting material was removed.

Another way we use information is to decide which objects are in greatest need of treatment. Given a limited amount of time, objects that could just use a surface cleaning to spruce up their appearance may have to wait three months if there’s another object in danger of falling apart! One of the more major treatments undertaken for the Seleucia exhibition was the desalination of this vessel, which showed a frightening patch of salt crystals around the rim and handle.

brittany4-5 — Left: detail image of salt crystals on the surface of a ceramic vessel (IL2012.04, TMA 1931.144). Right: the ceramic vessel in a desalination bath, with the probe of a conductivity meter immersed to measure the concentration of the remaining salts.

Archaeological objects are exposed to numerous substances during burial, the source of which can be the soil, materials dissolved in liquid water moving through the site, or even the object itself, perhaps from manufacture. Salts of the water-soluble variety can be dangerous when they enter the body of a ceramic or other porous object, simply because the crystals can expand and contract with changes in the humidity of the air. Expansion, as you can imagine, places a lot of stress on something, especially if it’s expanding from the pores within. To combat the salts, conservators perform what we call desalination: in these cases where the vessels are well fired with no surface decoration, we immerse the vessel in a bath of specially purified water. The idea is to flush the salts out of the ceramic, while tracking the progress with a meter that measures the presence of the dissolved salts in the water. If the vessel had had surface decoration, the process would have been trickier; likewise, if it had been poorly fired, or even fired at a low temperature, it would have run the risk of disintegrating completely in the water. Thankfully, we determined that this vessel was good to go for the desalination bath — and by all counts, was successfully rid of its soluble salts.

As you can see, we do keep busy in the conservation lab — and the Seleucia exhibition was no exception!

Conservation for Seleucia Show, Part 3 Read More »

Conservation for Seleucia Show, Part 2

Leave a Comment / Conservation / March 6, 2014

BY BRITTANY DOLPH, Graduate Conservation Intern, UCLA/Getty Conservation Program

Last month, I discussed the documentation aspects of conservation, especially as it pertained to our preparation of objects for the exhibition Life in Miniature: Identity and Display at Ancient Seleucia on the Tigris. Often, when time allows, conservation research can contribute technical information about objects, revealing how the artifact was made and even how it was used during its “life.” Furthermore, technical data aid us in making treatment decisions later on. Though we didn’t have the chance to do additional chemical analysis for this particular exhibition, we used different types of imaging techniques to get as much information as possible. And using different kinds of light in different ways for gathering information is ideal because it allows us to avoid taking samples. For example, a visual assessment can reveal seams, showing us that the miniature ceramic figurine below was made in two separate clay pieces before being joined together and fired.

This ceramic figurine, photographed from the rear, shows a seam running along the contour of the left side from bottom to top. Fingerprints are visible along the seam as well, where the maker attempted to bridge the sides by pushing the clay over.

A look through a simple binocular microscope can show tool marks that provide clues to how an object was made. For example, a stone figurine could have been roughly cut to size using a chisel or claw, then carved with final tools, and perhaps filed to create a smoother surface. In other cases, microscopy can reveal the remnants of pigment applied to a surface. In addition, condition problems such as micro-cracks, spots of metal corrosion, and many other issues are identified.

Conservators also often flash ultraviolet irradiation (sometimes incorrectly referred to as light) onto the surface of objects. Different materials react differently to the UV, so that we can often tell where additional materials have been applied by the color, strength, and opacity of their fluorescence or lack thereof. It can be especially helpful for finding previously applied conservation or repair materials.

Visual assessment . . . microscopy . . . UV . . . what do we do with all of this information? It helps to us to make decisions — which, it turns out, is a big part of the job! The first step is to decide whether or not even to treat an object. If we decide that treatment is necessary, we then have to decide how to go about it and what materials to use.

Next month, we’ll take a look at examples of treatments — and situations where we might decide not to treat at all.

Conservation for Seleucia Show, Part 2 Read More »

Conservation for Seleucia Show, Part 1

Leave a Comment / Conservation / February 4, 2014

BY BRITTANY DOLPH, Graduate Conservation Intern, UCLA/Getty Conservation Program

The Kelsey Museum of Archaeology recently opened an exhibition entitled Life in Miniature: Identity and Display at Ancient Seleucia on the Tigris. In the museum’s conservation department, we worked on the preparation and documentation of about 400 objects for this exhibition. Though these are mostly miniatures, an object’s size is by no means an indication of how much time we spend on it! Over the next few months, I’ll talk about the type of work we do with museum artifacts, especially as related to the Seleucia exhibition.

Our job starts by writing a report for each object to document its current condition. This document, complete with photography, serves as a sort of snapshot in time; if disaster strikes, whether in the form of a clumsy but well-meaning visitor, an unexpected tornado, or (more likely) the normal deterioration experienced by all objects over time, we then have a baseline record to determine the exact nature of the changes. The report involves a diagnosis of any problems with either the structure or the surface of the artifact — not unlike when you go to the doctor and he or she diagnoses you with a broken bone. This also allows us to figure out which objects need a little more care. For example, the ceramic jug (below left), with surface glaze that was continuously flaking off, was at higher risk than one on the right, which just had a little dirt.

Seleucia Blog 1 — On the left is a glazed ceramic jug (IL2012.04, TMA 1931.243) with areas of actively lifting glaze. On the right is the rear view of a fragment of a Parthian figurine depicting a female musician, with patches of dirt covering much of the surface.

We also document any changes we make to the artifacts. When conservation treatment is required, we keep a detailed record of the reasons and goals for the treatment. We include a list of any questions we tried to answer, and how we investigated them. (More about investigations coming next month!) What did we learn, and how might it affect how we treat the object? What materials did we use? How did we apply those materials to the object?

All of this information is included in the report, like your personal chart at the doctor’s, because it may be important for a future conservator, archaeologist, or other museum staff to know the “personal” history of that artifact when making their own decisions. It’s also important for us to remember that these artifacts already have a very long history: they were everyday objects belonging to people like us about 2,000 years ago.

Conservation research can also contribute other types of knowledge about an object, revealing how it was made and even how it was used during its “life.” Next month, I’ll talk about how we go about these investigations and what kinds of mysteries we may be able to solve!

Conservation for Seleucia Show, Part 1 Read More »