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The conserved and restored Yup'ik mask with Mel Wachowiak, Katharina Geier and Greta Hansen.

 

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Yup'ik mask. According to Edward Nelson, this mask "represents the tunghâk or being that controls the supply of game. It is usually represented as living in the moon. The shamans commonly make a pretense of going to him with offerings in order to bring game into their district when the hunters have been unsuccessful for some time.

"Masks of this character are too heavy to be worn upon the face without additional support, so they are ordinarily suspended from the roof of the kashim by strong cords. The wearer stands behind with the mask bound about his head, and wags it from side to side during the dance so as to produce the ordinary motion. I was told that in all the great mask festivals several of these huge objects were usually thus suspended from the roof."

From Nelson, The Eskimo About Bering Strait. 18th Annual Report of the Bureau of American Ethnology, 1896-97, Part 1 (Washington, DC, 1899), page 400.


LEARN MORE ABOUT IT
Katharina Geier’s thesis and analytical reports will soon be available on the SCMRE web site.

 

 

 

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Jakki Godfrey takes colorimetric measurements of Seminole garments.


How Colorimetry Works

The CIE L*a*b* color measurement system describes and orders colors graphically and numerically through a color coordinate plane that is consistent with human visual perception.

The system describes and orders colors by an opponent-color scale, which is based on the Opponent-Color Theory: if something is red, it cannot be green at the same time (but it may also be blue or yellow) and if something is yellow, it has cannot be blue at the same time (but it may also be red or green).

 

CIE L*a*b* Color Space

L*: the lightness coordinate

a*: the red/green coordinate, with +a* indicating red, and -a* indicating green

b*: the yellow/blue coordinate, with +b* indicating yellow, and -b* indicating blue.

 

 

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Kathy Tschappat cleans a Makah woven basket made of red cedar. Our catalog records indicate this basket would have been used for storing dried fish.

 

 

 

 

 

 

 

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An unusual glove, knit from the fiber of a Mediterranean mussel (Pinna nobilis Linne).

 

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Volunteer Joyce Murrell removing cotton from the mussel fiber glove.

Anthropology Conservation Laboratory
What's New for March 2004

Conservation and Study of Two Yup’ik Masks

Two Yup'ik ceremonial masks – the largest examples in the Department of Anthropology's collections – were chosen by Katharina Geier as the subject of a master's thesis undertaken for the University of Applied Sciences Erfurt (Germany). Geier discovered the masks during the course of her 4th year internship at the Smithsonian Center for Materials Research and Education, where she is working with senior furniture conservator Mel Wachowiak. The carved wooden masks, collected by Edward Nelson during the 1880s, are painted and decorated with feathers. They closely resemble each other and share the same materials and techniques of construction. Both masks have the prominent facial features, attached arms that extend directly from their mouths, side bars, two labrets, and attached carved animals. They also appear to be painted in the same manner with the same colors. At some point in their history the masks were disassembled. [Mask 1] [Mask 2]

When Geier consulted illustrations in the anthropology department's ledger books and Nelson’s own monograph (see sidebar), she learned that many pieces of the masks were no longer associated with them. She managed to locate fifteen of the detached pieces in various Arctic storage units after many hours of searching. She was able to positively associate these detached pieces with their original masks because the masks and their various parts included field number markings, and because pieces of broken dowels in the detached items could be matched to each mask.

Katharina and staff scientists analyzed the materials and techniques of manufacture of the masks to gather technical information that served as the background for conservation and restoration. The pigments and binders used, as well as the paint application, are still under investigation and the analytical results will be published. This new set of analytical data, derived from objects of a generally known age and origin, will serve as a reference for future studies of objects from the Arctic region.

A treatment proposal for the masks was drafted after consultations with Greta Hansen and Arctic curator William Fitzhugh, to ensure that the treatment would be compatible with departmental objectives and philosophy. Following the treatment, the masks were reassembled and restored to some extent. Long-detached parts were reattached to the masks and lost parts were reconstructed by comparison of the masks to existing drawings and photographs [Mask 1]. Due to the symmetry of the objects, additional information about missing parts was obtained through the examination of the opposite sides of the masks. The replacements were carved from wood and inpainted using dry pigments and water colors. Each inpainted replacement carving was marked on its back in pencil with the date of its creation (2003). Like the original parts, they were carved with dowel attachments and inserted into already existing drilled holes. In addition, missing feathers in mask 2 were replaced with new swan feathers at the request of Fitzhugh, who believed the restoration would return the masks to their original impressive and powerful appearance.

Colorimetric Analysis of Seminole Textiles

One way that conservators determine whether a material's color has faded over time is by comparing before and after photographs of objects. But our experience of color differences in photographic samples is relatively subjective. A more accurate method is tristimulus colorimetry, which measures color change quantitatively. Colorimetry creates permanent data that is precise, accurate and reproducible. Using the CIE L*a*b* color measurement system (see sidebar at left), colorimetry measures differences in lightness, hue and chroma between two samples. It can also measure the total color difference.

The ACL first used colorimetry to analyze Seminole garments that were exhibited for twelve years (1989-2002) in the National Museum of Natural History. When the exhibit was originally installed, the garments were displayed using low light levels and UV filters to reduce the deterioration and fading of objects. However, the garments remained on display far longer than expected and their prolonged exposure to light caused severe, irreversible fading. Project consultant Mary Ballard (senior textile conservator of SCMRE) proposed using instrumental color evaluation with tristimulus colorimetry to measure the exact extent of the fading. Jakki Godfrey, pre-program intern at the ACL, performed the colorimetry measurements on the Seminole garments.

The results of the trisimulus colorimetry test provided objective, quantifiable evidence that the Seminole textiles faded after a period of twelve years – even under standard low-level exhibition lighting. As a result, the original intention of the Seminole craftsman – the selection and juxtaposition of certain hues – has become distorted. ACL staff plan to perform colorimetry on fragile artifacts before they are placed on exhibit in the future to provide a baseline against which color change can be measured. With regular monitoring, it should be possible to remove susceptible objects from exhibit before a color damage limit (such as _E = 2.0) is reached.

A Fragile Makah Cedar Bark Basket

When researcher Melissa Peterson visited the Anthropology Department to examine Makah cedar bark baskets, she discovered a large collapsable basket collected by James G. Swan at Cape Flattery on the northern coast of Vancouver in 1874. The basket was too fragile to examine, however, because it had been sharply folded sometime before it arrived at the Smithsonian. To make the basket flexible enough to open safely, it was taken to the Anthropology Conservation Lab for humidification and cleaning.

As conservators opened the basket to reveal its original shape, they noticed that its unexposed surfaces were lighter and cleaner than the exposed surfaces, which were dark with a sooty material (probably as a result of industrial pollution). First the soot was carefully removed with small-celled, soft cosmetic sponges (Qosmedix®). Then the folding creases were humidified so that the basket could slowly be returned to an open configuration. It was then possible to see the actual shape of the basket, the design, and the weaving pattern. The creases were not actually removed, only softened, because prolonged folding had imparted a crease "memory." Many of the basket's fibers had broken along the creases and in some cases the crease was actually cleaved, leaving a crack in the weaving.

Before returning the basket to storage, the basket was placed on its long side, which provided the most support – sitting it on its base wasn’t an option because the edges of the base were too broken from prolonged folding. ACL volunteer Kathy Tschappat fashioned an interior support from blueboard so that the interior of the basket would remain visible for researchers and would discourage removal of the support. In addition, the box had to support the sides with gentle pressure, so it was tied together in the front and back. The ties also would allow for easy removal if that were necessary, as the sides of the box would fall away with the tie opening.

Silk from the Sea: A Mussel Fiber Glove

An unusual hand glove, knit from mussel fiber, was brought to the Anthropology Conservation Laboratory for rehousing by the Museum's Division of Mollusks. The dark tan glove, originally from Tarento, Italy, is somewhat rough to the touch. It is made from the fiber of Pinna nobilis Linne, a mollusk species endemic to the Mediterranean. The fiber is called byssus, a tuft of filaments by which certain bivalves fasten themselves to rocks. Byssus is a strong fiber and has long been used for fabrics.

The glove had been stored in a traditional Riker box (a glass-lidded box in which fragile objects are stored on a cushion of cotton wadding under slight pressure from the lid). Such long-term storage had resulted in a flattening of the glove and sharp edge creasing which would be prone to fracturing over time. For more appropriate and safer storage, we determined that the sharp edge folds of the flattened glove needed to be relaxed and the newly configured glove stuffed with a relatively thin material to reduce further creasing.

The glove responded well to gentle humidification and the sharp folds, particularly along the fingers, were reduced. A storage insert was designed using Volara®, a cross-linked polyethylene foam, pliable, but fairly stiff, and about 1/8” thick. Initially a foam piece was cut following the contours of the glove, with appropriately sized finger inserts to reduce stress and creasing there. Inserting the contoured form proved difficult and potentially damaging, stretching the glove at its opening. To solve this problem, the insert was cut into 5 narrow pieces, one for each finger. These could be slid into the glove with no stress. The Volara® edges were smoothed by carefully using a heat gun and the pieces were labeled 1 through 5 so that anyone studying the glove could easily remove and replace them. After final placing of the finger pieces, the glove was placed on a muslin-covered cushion containing heat-bonded polyester fiber fill made to fit exactly in a new archival Riker box. The cushion was designed to place the glove almost in contact with the glass of the box lid. The muslin, which offers enough knap and friction to hinder the movement of the glove, would not shed fibers as the cotton fibers from the original Riker box housing had done.

As one might wonder who thought of using caterpillar cocoons to weave beautiful silk garments, one might as naturally wonder about the use of mussel fibers in knitting. Maybe we could call byssus the "silk of the
sea"!

 

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