UCLA/Getty Conservation Program

A graduate conservation training program focusing on the conservation of archaeological and ethnographic materials


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UCLA/Getty Program Welcomes Visiting Scholar Dr. Pujun Jin

The UCLA/Getty Conservation Program welcomes visiting scholar Dr. Pujun Jin, who will be with us through November 2016.  During his time here, he will be working Dr. David Scott examining ancient Chinese bronzes. Dr. Jin joins us from the School of Materials Science and Engineering, Shaanxi Normal University, China.  He received his Ph.D. in Scientific History and Archaeometry from the University of Science and Technology of China. His current research focuses on the metallurgical examination of artifacts excavated from the site of Sanxidui dating to the Shang Dynasty.  He is also studying the lost-wax technique used to cast a bronze mou (cooking vessel) from the Ba Culture and the corrosion and conservation of ancient Chinese plated bronzes.

Pujun Jin


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UCLA/Getty Program Welcomes Mellon Fellow in Conservation Education Laleña Vellanoweth

The UCLA/Getty Program is pleased to welcome Laleña Vellanoweth as the Andrew W. Mellon Fellow in Conservation Education for the 2015-16 academic year.

Laleña is a Costume and Textile Conservator. She received her B.S. in Biochemistry and B.A. in Art from California State University, Los Angeles and her M.A. in Art History and Certificate in Conservation from the Institute of Fine Arts at New York University. She has worked at the Costume Institute at the Metropolitan Museum of Art, the Museum of Modern Art, the Autry National Center, and Los Angeles County Museum of Art.

As part of her Mellon Fellowship, she will be researching diversity in art conservation and surveying parallel diversity programs for other museum fields. She will also be working on a research project on Californio costume, focusing on a technical study of three charro suits from the early nineteenth century, one of which was worn by Don Vincente Lugo, a member of one of the founding families of Los Angeles. Laleña will also give lectures on textiles and costume, including fiber identification and costume mounting.

IMG_2394


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Welcome Class of 2018!

Today we welcomed the start of fall (despite the warm LA weather), and the new incoming class of the UCLA/Getty Program!

The class of 2018 will begin their first day of instruction tomorrow with a course focusing on documentation and imaging techniques.  They’ll also have the opportunity to take classes this quarter that cover the technology and deterioration of ceramics and glass, principles and ethics in conservation, and science fundamentals in conservation. Two of their courses include object-based projects where they will examine, document and assess the condition of a group of pre-Columbian ceramics from the collection of the Fowler Museum at UCLA.  Between their course and lab work, it looks like we will be keeping them pretty busy this quarter!

We wish the class of 2018 good luck with their coursework and lots of success in the conservation program!

From L to R: Marci Burton, Lindsay Ocal, Hayley Monroe, Michaela Paulson, Morgan Burgess, Mari Hagemeyer

The class of 2018! From L to R: Marci Burton, Lindsay Ocal, Hayley Monroe, Michaela Paulson, Morgan Burgess, Mari Hagemeyer


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“Animal, Vegetable, Mineral?” – Identifying mystery fibers in the field

When conservators are working on archaeological excavations, their work often encompasses many different aspects of field conservation.  This can include materials identification and characterization, lifting fragile artifacts and aiding in archaeological research.  No matter what facet of the project they are involved in, the work can be challenging without the comforts of a well-stocked lab and requires lots of problem solving and improvisation.  Last summer while working on the Ancient Methone Archaeological Project, we were faced with the challenge of trying to identify an unusual looking fibrous material which required us to MacGyver a transmitted light microscope to aid in the examination and identification of the mystery fibers.

During the 2014 season, a team of geomorphologists working on the project were taking core samples in an area thought to be an ancient harbor.  In one of the cores, they pulled out a clump of fibers they thought might be cordage (fig. 1).  They brought the samples to the conservation lab to see if we could identify the fibers and determine if it was cordage or the remnants of woven fibers. Some samples were set aside for radiocarbon dating and the remainder of the sample, which was still bound in sediment, was examined.

Figure 1. Clump of fibers found in soil core by Geomorph team. Photo: Ancient Methone Archaeological Project

Figure 1. Clump of fibers found in a core sample taken by the Geomorphology team. Photo: Ancient Methone Archaeological Project

The initial macroscopic examination revealed that the fibers appeared translucent (fig. 2).  They seemed to be grouped into bundles and some of these bundles initially appeared to cross each other, giving the impression of a woven structure.

Fgiure 2. Detail of the fibers encased in the sediment.  The fibers are translucent and are grouped in bundles.  Photo: Ancient Methone Archaeological Project

Fgiure 2. Detail of the fibers encased in the sediment. The fibers are translucent and are grouped in bundles. Photo: Ancient Methone Archaeological Project

The fibrous material was encased in a gray, silty sediment, which appeared to include quartz, foliated phyllosilicates/sheet silicates (like mica, vermiculite, etc.) (fig. 3), as well as small shells, both fragmented and whole (fig. 4). The sample was initially wet, and was allowed to slowly dry out in the lab. The sediment was gently pushed away using a pin-vise under binocular magnification, to better define the structures and reveal diagnostic features of the material for its identification (fig. 5).  Photographs of the fibers were taken using the DinoLite USB microscope (7013MZT Series). During this examination and initial cleaning, the fibers were found to be very brittle.  Though they appeared to be in bundles, they were not actually bound to each other and could be easily separated.

Figure 3.  During cleaning, plate-like inclusions were found in the soil and between the fiber bundles.  These inclusions resembled sheet silicates like mica. Photo: Ancient Methone Archaeological Project

Figure 3. During cleaning, plate-like inclusions were found in the soil and between the fiber bundles. These inclusions resembled sheet silicates like mica. Photo: Ancient Methone Archaeological Project

Figure 4.  Small shells or shell fragments were also found in the deposit. Photo: Ancient Methone Archaeological Project

Figure 4. Small shells or shell fragments were also found in the deposit. Photo: Ancient Methone Archaeological Project

Figure 5.  After some initial cleaning to remove soil, more of the fiber bundles and associated materials are visible. Photo: Ancient Methone Archaeological Project

Figure 5. After some initial cleaning to remove soil, more of the fiber bundles and associated materials are visible. Photo: Ancient Methone Archaeological Project

Though examination with a stereomicroscope helped to reveal more about the fibers and the structure of the bundles, we were not able to clearly identify what the fibers were.  We felt that examination using transmitted light microscopy would be the most helpful since it could highlight any morphological features in the fiber that could aid in identification.  So we set out to make one armed with our DinoLite microscope and a flashlight. The set up turned out to be quite simple. We just needed to be able to shine a light through the fibers from below and examine the fibers at a high magnification using the DinoLite (fig. 6). We took a fiber bundle from the sediment and placed it on a multi-bulb LED flashlight (fig. 7).  This flashlight was flat and rectangular and the ideal shape for our light source since the fiber samples could be directly placed on the top surface of the flashlight.  The fact that the flashlight was flat also meant it was easy to position the light source under the microscope where needed (fig. 8).

Figure 6.  We created a transmittled light microscope using the DinoLite USB microscope and an LED flashlight which acted as the transmitted light source. Photo: Ancient Methone Archaeological Project

Figure 6. We created a transmittled light microscope using the DinoLite USB microscope and an LED flashlight which acted as the transmitted light source. Photo: Ancient Methone Archaeological Project

Figure 7. We placed samples of the fibers directly onto the flashlight during examination. Photo: Ancient Methone Archaeological Project

Figure 7. We placed samples of the fibers directly onto the flashlight during examination. Photo: Ancient Methone Archaeological Project

Figure 8.  Using our transmitted light  microscope to examine the fibers.  Macguyver would be proud. Photo: Ancient Methone Archaeological Project

Figure 8. Using our transmitted light microscope to examine the fibers. Macgyver would be proud! Photo: Ancient Methone Archaeological Project

Looking at the fibers in transmitted light, we observed a central void within some of the fibers.  Since we were considering the possibility of the fibers being organic in nature, we thought these central voids could be the medulla or lumen of an organic fiber (fig. 9). However, no other morphological features were present that helped us determine at this point what the fibers were.

Figure 9. Looking at the fibers under transmitted light, we could see they had a central void, which initially made us think this was the lumen of a plant fiber or medulla of an animal fiber. Photo: Ancient Methone Archaeological Project

Figure 9. Looking at the fibers under transmitted light, we could see they had a central void, which initially made us think this was the lumen of a plant fiber or medulla of an animal fiber. Photo: Ancient Methone Archaeological Project

We were also able to take a look at the cross-section of the fibers with the addition of a polarizing lens on the DinoLite (fig 10). Some fibers appeared hexagonal in section (fig. 11).  Some of the ends of the fibers ended in a point or were triangular in shape.

Figure 9.  With the addition of a polarizing lens on the DinoLite we were able to see the cross-sections of some of the fibers.  Some appeared hexagonal or triangular in section. Photo: Ancient Methone Archaeological Project

Figure 9. With the addition of a polarizing lens on the DinoLite we were able to see the cross-sections of some of the fibers. Some appeared hexagonal or triangular in section. Photo: Ancient Methone Archaeological Project

Figure 11.  Details of the fibers showing their shape in section.  Photo: Ancient Methone Archaeological Project

Figure 11. Details of the fibers showing their shape in section. Photo: Ancient Methone Archaeological Project

Further cleaning revealed a tiered growth structure that resembled the growth of minerals more than plant or animal fiber bundles (fig. 12).  The inclusion of sheet silicates in relation to the fibers, either located between bundles or within them further suggested these fibers were mineral.  In searching the literature we came across images of asbestos minerals which looked similar to our mystery fibers.  Several types of asbestos minerals are fibrous in appearance (fig. 13), and can occur near phyllosilicate deposits.  Armed with this information we concluded that the fibers were definitely mineral in nature and could possibly be asbestos.

Figure 12.  Fiber bundle after cleaning. Photo: Ancient Methone Archaeological Project

Figure 12. Fiber bundle after cleaning. Photo: Ancient Methone Archaeological Project

Figure 13. An image of crocidolite, a fibrous form of the mineral riebeckite, and one of the 6 recognized forms of asebstos minerals.  © Raimond Spekking / , via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/b/b3/Krokydolith_-_Mineralogisches_Museum_Bonn_%287385%29.jpg

Figure 13. An image of crocidolite, a fibrous form of the mineral riebeckite, and one of the 6 recognized forms of asebstos minerals. © Raimond Spekking / , via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/b/b3/Krokydolith_-_Mineralogisches_Museum_Bonn_%287385%29.jpg

Luckily we were able to bring a sample of the fibers back with us and conduct some analysis in the UCLA/Getty Conservation labs. And we were quite surprised by the results!  It turns out we were correct in deducing the fibers were mineral in nature, but we were incorrect about which mineral. XRF and XRD analysis did not find any asbestos minerals in the sample, but instead the fibers were identified as calcite (fig. 14).  Though we had never seen calcite that was fibrous in appearance, it is one of the mineral’s crystal forms. An example is shown in fig. 15 where you can see the SEM image of “lublinite”, a needle-type of calcite whose form is thought to be associated with the activity of microorganisms.

Figure 14. XRD analysis results showing the fibers were composed of calcite.

Figure 14. XRD analysis results showing the fibers were composed of calcite.

Figure 15. SEM image of lublinite, the fibrous form of calcite.  Image taken from: http://www.speleonics.com.au/jills/bymineral/lublinite.html

Figure 15. SEM image of lublinite, the fibrous form of calcite. Image taken from: http://www.speleonics.com.au/jills/bymineral/lublinite.html

Even though we were not able to identify the fibers as calcite in the field, the use of a stereomicroscope and our makeshift transmitted light microscope certainly helped distinguish their mineral nature and rule out plant or animal origins.  And now that we’ve figured out how to make a transmitted light microscope and tested it out, we’re ready for any future material ID questions that would require one.

MacGyver looks on and smiles at our ingenuity.  Photo: http://macgyver.wikia.com/wiki/List_of_problems_solved_by_MacGyver

MacGyver looks on and smiles at our ingenuity. Photo: http://macgyver.wikia.com/wiki/List_of_problems_solved_by_MacGyver

Written by the 2014 Ancient Methone Archaeological Project Conservation Team: Heather White (UCLA/Getty Program Grad Student, Class of ’16), Vanessa Muros (Conservation Specialist/Lecturer, UCLA/Getty Program) and Anna Weiss (Campus Art/Artifact Collections Coordinator, Conservator, Univ. of Chicago)


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The Conquistador’s Coat: Characterization of a surface coating on a Guatemalan polychrome mask

This past spring quarter, for the course “Conservation Laboratory: Organics III”  (CAEM 241), I had the opportunity to examine and treat a polychrome mask (X91.470) from the collection of the Fowler Museum at UCLA.  The polychrome mask is made of carved wood  and is  likely meant to depict the face of a conquistador, with detailed curling hair, a long beard and mustache, and a light complexioned, pink face.

Masks such as this one are commonly used in ceremonial dances in Guatemala, and one such as this may have been used in the Dance of the Conquest, a dramatic dance that depicts the Conquest of Guatemala by the Spanish in 1524 (Pieper 1988: 39) . You can see a portion of this dance in this YouTube video, where several of the dancers are wearing a mask similar in appearance to the Fowler conquistador mask.

The mask is painted with thick layers of paint that are currently heavily obscured by a thick accumulation of soiling that is likely on top of a discolored surface coating. Guatemalan dance masks are traditionally professionally maintained by costume shops called morerias, which apply fresh paint to keep them looking new.  The age of the mask is not necessarily considered a marker of value, and it is actually preferred that the masks look new and well maintained when they are danced.  Some masks may be blessed by an indigenous Shaman or Catholic priest (Pieper 2006: 43-45) .  Historic accounts of the maintenance of these masks do not refer to the application of any surface coatings as a protective measure for the polychromy.

Description of the coating

The majority of the painted surface of the mask is obscured by a thick layer of a dark, grimy material with embedded soiling (fig. 1-2).  It is unknown when or for what purpose the coating was applied to the mask, but it may have been applied for surface protection of the polychrome or to consolidate flaking paint.

Fig_1a_X91.470 Fig2c_X91.470

Figures 1 and 2. An image of the front of the Conquistador’s mask (X91.470) (left) with a detail (right) of the area of the nose showing the discolored surface coating.

Under stereo binocular magnification (7-45x), the material has a varied appearance, at times appearing like a matte coating that is heavily embedded with soiling of a granular nature (fig. 3), at times flaking (fig. 4), and in other instances appearing thinner, with a somewhat sticky texture, but less accumulated matte material (fig. 5).

Fig3_X91_470_07X

Figure 3. Soiling on the mask that is granular in nature

Fig4_X91_470_07X

Figure 4. Dark surface material that is flaking.

Fig5_X91_470_07X

Figure 5. Some of the dark material on the surface appeared thinner and sticky, and some areas had a matte appearance.

There are also areas where the surface coating has a wrinkled appearance, as if it has shrunk and pulled away from the surface, and in these cases it appears to be pulling the paint layer with it (fig. 6).  The wrinkled areas look the way that paint looks when a commercial paint stripper is applied.  In all of its iterations, it appears to be inextricably linked with flaking paint layers beneath it (fig. 7).

Fig6_X91_470_07X Fig7a_X91_470_1X copy

Figures 6 and 7. In some areas the surface coating appears as if it shrunk and pulled away (left). Regardless of the appearance or texture of this coating it is inextricably linked with flaking paint layers (right).

There are a few areas where the obscuring dark coating is not as present.  In these areas, it appears that there may have been an attempt to remove it, which resulted in peeling away of the top paint layer as well (fig. 8a and b).  In these instances, the pink paint film has been pulled away and is folded over onto the surface of the mask and adhered in place. The areas of folded paint film appear to be brittle and have shattered in some locations along the edges.  There is a sticky, light brown resinous material that has accumulated in the crevices of these surfaces, which is likely deposited residue from the surface coating. In addition, a distinct layer of soiling has accumulated on top of the coating.  Much of the soiling appears embedded within the coating, but there is also loose surface dirt that can be moved with a soft brush.

Fig8a_X91.470 Fig8b_X91_470_07X_
Figures 8a and b. In some areas, it appears as if there was an attempt to remove the coating (left) which resulted in peeling away of the top paint layer (right).

UV Examination

The object was illuminated with ultraviolet radiation at λexcmax=300-400nm and captured with a Nikon D90 digital camera affixed with the PECA 916 filter (visible range). The soiled coating that covers the face appears largely absorbing.  Areas of fluorescence occur where the flesh colored paint is exposed without the coating (fig. 9).

Figure 9. Under examination with a UV light (λexcmax=300-400nm) the soiled coating appears largely absorbing.  Areas of fluorescence occur where the flesh colored paint is exposed without the coating.

Figure 9. Under examination with a UV light (λexcmax=300-400nm) the soiled coating appears largely absorbing. Areas of fluorescence occur where the flesh colored paint is exposed without the coating.

Solubility Testing

Solubility testing was conducted in situ on the mask with room temperature deionized water, warm deionized water, acetone, ethanol, toluene, and mineral spirits.  The coating was unresponsive to cool water, acetone, ethanol and mineral spirits, but a slight change in appearance was noticed when toluene was applied, though none of the coating was removed onto the swab.  This surface change was fleeting and the coating returned to its original appearance immediately.  Just to be certain that the coating was insoluble in toluene, the application of toluene on a small sample of coating that had flaked off of the surface was observed under stereo binocular magnification at magnifications of 7-45x.  No dissolution or swelling of the coating material was observed (fig. 10).

Figure 10. No dissolution or swelling of the coating material was observed in toluene.

Figure 10. No dissolution or swelling of the coating material was observed in toluene.

The mask was undergoing treatment because the painted surface was unstable and was lifting and flaking.  Gelatin was under consideration as a consolidant for the flaking paint and therefore warm water was also tested to ensure that a warmed gelatin solution could be used without disrupting the appearance of the coating.  Unfortunately the warm water was found to swell and eventually solubilize the coating so that it could be swabbed away with gentle pressure.  The interaction of the coating with warm water was further investigated by observation under stereo binocular magnification.  As the sample soaked in the warm water the brown material on the sample surface swelled into fluffy blobs on top of a more transparent, clear base.  Over a period of time the clear, striated section of the sample also appeared to swell slightly (fig. 11).  Because warm water was observed to have an effect on the coating, a small cleaning test was conducted in a discreet area of the mask using warm deionized water applied by swab under stereo binocular magnification.  The coating was greatly reduced using this method and it is very likely possible that it could be removed simply using warm water, if removal were desired.  Though the solubility in warm water introduced a possible complication with using a warm, aqueous consolidant such as gelatin, the fact that the gelatin would remain soluble in water was also a possible advantage to using this consolidant; should the removal of the consolidant be desired in the future, it would be beneficial if it was not consolidated in place with a system using toluene (the only solvent besides water that did not affect the paint layers below) for toxicity reasons.

Figure 11.  Swelling of the coating was observed in warm water.

Figure 11. Swelling of the coating was observed in warm water.

Additional Microscopic Observations

Two small samples of the pink paint was removed from a discreet area of the mask where the paint layer contained a layer of the dark coating and was observed to be flaking.  This flake was viewed in transmitted light using an Olympus BX-51, polarized light microscope at magnifications between 50-200X.  Using this technique, it was not possible to observe the layers as distinct entities, however, at the edge of the paint flake and within interstices of the flake, small sections of the coating could be observed.  It appeared to have a somewhat clear and amorphous structure (fig. 12a and b).

Fig14a_x91_470_coating_11 Fig14b_x91_470_coating_21).
Figures 12 a and b. Examination of a paint flake with the coating viewed under transmitted light.

In addition, several small samples of the coating were removed from the mask during a light surface cleaning procedure.  These samples were soaked in warm water as described above, in order to further characterize the solubility of the material.  These samples were viewed in transmitted light under high magnification and also in cross-polarized light. (fig. 13a and b) The samples appeared to swell from exposure to the water.  The material was quite clear, and had the appearance of an organized cellular structure in some areas.

Fig15a_x91_470_coating_31 Fig15b_x91_470_coating_32
Figures 13a and b. Examination of the coating using transmitted (left) and cross-polarized light (right) after swelling in warm water.

Spot testing

Two microchemical tests were conducted in the hope of possible identification of materials present: a test for polyamides using p-dimethylaminobenzaldehyde (Odegaard et al. 2000: 170-171), and a test for protein using copper (II) sulfate (Odegaard et al. 2000: 144-145).

The test for polyamides was conducted to confirm or deny the presence of nylon, had the mask been treated with soluble nylon (N-methoxymethyl nylon, a chemically modified form of nylon that is produced by treating nylon with formaldehyde). Soluble nylone was a common consolidative conservation treatment for powdering or flaking paint beginning in the late 1950s.  Objects that have undergone treatment with soluble nylon have been observed over time to exhibit numerous problems including accumulation of disfiguring and obscuring soiling in the nylon film, the film exerting strong contractile forces which peel away surface layers from objects, and the film losing flexibility and becoming insoluble (Sease 1981).  These descriptions of the degradation characteristics of soluble nylon in the literature were similar to the appearance of the coating on the Fowler mask. Neither the age of the mask nor its conservation history are known, and it was possible it could have been treated at a time when soluble nylon was a popular conservation treatment. The result of the spot test was negative and was compared to a known positive result (color change to red of filter paper used in the test) from a nylon sample taken from the ResinKit™.

The protein test was conducted because of the coating’s swelling effect in warm water.  In addition, from the literature it is known that at high RH levels animal glue films can experience severe shrinkage due to contraction of the glue matrix, and in some instances the coating appears to be undergoing contractile shrinkage as described (Schellmann 2007).  The result of the protein test was negative and was compared to a known positive sample of gelatin.

Conclusion

Based on the above observations and testing, the material constituents of the coating could not be identified.  Nylon-based (such as soluble nylon) and protein-based (such as animal glue) coatings were ruled out based on the spot testing results.  Knowing that the material is soluble in warm water is important information should the removal of the coating be desired in the future.  At this time, because the nature and purpose of the coating have not been identified, its removal would not be an appropriate course of action, so it will be left intact.  An additional problem posed by the presence of the coating is that the paint layers below it are flaking, and the coating may be contributing to or in fact causing the flaking.  In order to consolidate the paint layers below without removing the coating first, the coating and accumulated soiling also become consolidated as a result.  Even though warm water has the ability to swell or solubilize the coating, mechanical action is also required to remove it.

Though the warmed consolidant did have the potential to interact with the coating, care was taken to only flow the gelatin under lifting or detaching paint flakes and to try to avoid saturating the coating with consolidant.  This worked rather well in the areas of pink polychromy.  When cleaning was required around the consolidation site, this was done immediately, and the coating was not affected.  In the areas of the hair and beard, the nature of the coating was somewhat different, as described above (fig. 4).  When this iteration of the coating came into contact with the warm gelatin, it solubilized quite easily.  Again the focus of the treatment was consolidation of localized areas of active flaking or evident wood deterioration, and care was taken in choosing sites in which to introduce the consolidant by brush without disrupting the coating.  When the consolidant was applied with care under binocular magnification, the coating was not at risk of being removed.  Furthermore, by using this aqueous consolidant, the solubility of the coating in warm water should not be affected, should its future removal be desired.

References

Odegaard, Nancy, Scott Carroll, and Werner S. Zimmt. Material characterization tests for objects of art and archaeology. Archetype, 2000.

Pieper, Jeanne, and Jim Pieper. Guatemalan Masks: The Pieper Collection. Craft and Folk Art Museum, 1988.

Pieper, Jim. Guatemala’s Masks and Drama. University of New Mexico Press, 2006.

Schellmann, Nanke C. “Animal glues: a review of their key properties relevant to conservation.” Studies in Conservation 52, no. Supplement-1 (2007): 55-66.

Sease, Catherine. “The case against using soluble nylon in conservation work.” Studies in Conservation 26, no. 3 (1981): 102-110.


Written by Lesley Day (’16)


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Class of 2016 Summer & 3rd Year Internships

The quarter is coming to an end and students are busy finishing up treatments and thesis projects, as well as writing papers and studying for finals. On top of all that, they’re busy getting ready to leave LA for their summer and 3rd year internships. Below is a list of all the great places they’ll be working at in the upcoming year.

We wish them good luck on their internships and safe travels!


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ANAGPIC 2015, here we come!

Our students and faculty are getting ready to head east to attend the 2015 ANAGPIC conference this week. This year, the conference will be co-hosted by the Winterthur/University of Delaware Program in Art Conservation (WUDPAC) and the University of Pennsylvania’s graduate program in Historic Preservation. This is the first time that UPenn will be hosting ANAGPIC. They, along with Columbia University’s Historic Preservation program, joined ANAGPIC a couple of years ago. The addition of these programs broadens the scope of the papers presented and provides additional opportunities for students and preservation professionals to share information about their recent research and projects.

The UCLA/Getty Program will be well represented with 2 speakers and 4 posters. Abstracts of our program’s presentations are found below. For a full list of papers/posters presented and more information on the conference, you can check out the ANAGPIC 2015 website. And make sure to check out our Facebook page and blog for photos from the conference.


Papers

Torqua Cave: Documentation and Condition Assessment of Catalina’s Rock Images
Tom McClintock

The site of Torqua Cave is a rock shelter on Catalina Island, located 20 miles off the coast of Southern California. The largest of the Channel Islands, Catalina has a fascinating geologic history and is rich in marine and lithic resources. It was was inhabited at least 9000 years BP by the people known today as the Island Tongva. The first documentation of Torqua occurred in the early 1970’s with the identification of 19 red pictographs, although by today’s standards this campaign was not sufficiently systematic. To date there is little to no characterization of the site’s physical history.

This paper presents the results of new imaging technologies based on Decorrelation Stretch and an assessment of local climatic conditions and substrate composition, which will lead to a better understanding of the site’s history and deterioration. Following an assessment of condition, the significance of the site to its stakeholders, including the indigenous population, the island’s contemporary residents and its landowners, will be investigated.

Decorrelation Stretch is a method of producing false color digital images that is able to reveal severely faded pigmented decorative surfaces, which has been used successfully here to identify previously unrecognizable and invisible pictographs. Photogrammetry will be performed to create a unified image of the site, which, at roughly 50’ long and on a hillside, has not been possible to present previously. X-Ray Diffraction has identified the pigment used and the composition of its substrate. Portable x-Ray fluorescence (XRF) spectroscopy and ultraviolet/visible/near infrared (UV/Vis/NIR) reflectance spectroscopy will be performed on-site to create a map of the panels’ surface composition for comparison with visual characteristics such as color variation, patterns of deterioration, presence of water from various sources, and accretions. Polarized light microscopy (PLM) will be performed on a thin-section slide of the host rock’s substrate for identification of its composite minerals. Environmental data loggers will be placed at the site to measure ambient temperature (T) and relative humidity (RH) at the site through daytime/nighttime cycles for a year to compliment spot measurements of rock surface temperature, T and RH that were collected in summer 2014.

This information will be used to characterize the degradation patterns of the bedrock panels that comprise this site, focusing on the interrelationship of the rock’s composition, local climate and water transfer through the rock and from external sources. An assessment of the site’s significant and the danger of anthropogenic impact will lead to recommendations concerning future management strategies and protection.

An Analysis of Unidentified Dark Materials Between Inlaid Motifs on Andean Wooden Queros: Preliminary Findings
Heather White

Paramount in the study of Andean civilizations, past and present, are the people’s rituals and ceremonial customs which have pervaded the Inka and post-Inka periods. These rituals mark social and religious occasions with offerings to the gods that ensure economic prosperity and good health. Decorated wooden cups, called qeros, have facilitated these customs through the centuries, witnessing long use-lives as they are passed down from generation to generation. As custodians of ancient Andean rituals and ways of life, contemporary Andeans use the cups as their ancestors did: to hold and transfer libations of blood or the fermented maize beer chicha, to honor, respect, and celebrate religious, social, and economic activities. It is from here that qeros enter museum collections, their use-life ends, and their preservation as vestiges of Andean culture and ritual begins. In recent years there have been technical studies of Andean qero technology focusing on the materials used for the polychrome inlay decoration, identified as an array of natural and manufactured pigments bound by an organic resin from species of the Elagaeia tree (E. utilis and E. pastoensis), locally known as mopa mopa. However, currently there is a lack of information concerning the dark material(s) present around the polychromy, which exhibits peculiar and substantial loss on vessels in many museum collections, sometimes as though it has been physically scraped off. For this study, different dark materials surrounding the polychrome design on a group of qeros belonging to the Fowler Museum at the University of California-Los Angeles were investigated in an effort to characterize them and potentially explain the technical, cultural, and/or ethnographic reasons for their presence and causes for their loss. Various documentation and analytical techniques were employed, including visual analysis, digital photography, UV-induced visible fluorescence, Reflectance Transformation Imaging (RTI), microscopy, portable X-Ray Fluorescence (pXRF) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and Gas Chromatography-Mass Spectrometry (GC-MS). Preliminary results have shown surface modification and ethnographic wear which appear related to the material’s loss. Identifying this material(s), understanding its origin and explaining its loss will contribute to our knowledge of the vessels’ manufacture and/or ethnographic history and use, and guide our transferred custodianship over such artifacts of Andean traditions.

Posters
Technical study of a miniature Tuareg camel saddle using X-radiography and X-ray fluorescence spectroscopy
Elizabeth Anne Burr

A miniature camel saddle from the Fowler Museum is an example of the dyed leather and metal work for which the Tuareg of Niger are known. This saddle made by Hamidan Oumba for the tourist market is a replica of traditional tamzak camel saddles used by the Tuareg elite. It was suggested by an African art scholar that a miniatures such as this would be constructed using the same materials and techniques as a traditional tamzak with a wooden frame. However, X-ray imaging revealed a substrate that included more dense materials in addition to wood. X-ray fluorescence spectroscopy (XRF) data was acquired from a number of locations over different substrate materials (as corresponding to x-ray images), and different types of dyed leather, which were overlaid for interpretation. Correlations were found between the dense substrate material and the trace elements rubidium and strontium used to identify clays. This and the texture seen in X-ray image suggest that clay based components of the frame were manufactures for this object, a deviation from a traditional construction. Also, the turquoise leather was found to be rich in chlorine, copper, and tin, suggesting the use of bronze chloride corrosion to create the leather pigmentation as is traditional among the Tuareg. These results suggest a combination of both innovation and tradition in the construction of this art piece.

Diagnostic Imaging Techniques for the Identification of Tortoise Shell
Lesley Day

The focus of this poster is the documentation of a specific patterning, found within and unique to tortoise shell, made up of random swirling lines, which most likely correspond to the yearly depositions of keratin that occur as the turtle grows. This phenomenon has been observed in passing in some literature, but has not been fully characterized and is little understood in any discipline. The patterning has been observed as topography in some antique tortoise shell samples, and also as darkened lines in an example that appears to have suffered light damage. This poster will illustrate how documentation techniques including UV-induced visible fluorescence and Reflectance Transformation Imaging (RTI) have proven to be extremely useful in observing and documenting the pattern, and how characterization and further understanding of the pattern can be used as a diagnostic criteria for distinguishing tortoise shell from imitative materials such as plastic and horn.

The documentation illustrated in this poster is one component of my master’s thesis research about light-induced alterations to tortoise shell, and specifically how light may induce alterations to the patterning described, such as darkening and increased visibility. For the study, two taxidermied hawksbill turtles (Iretmochelys imbracata) were generously donated by the US Fish and Wildlife Department of Forensics, and the scutes from one turtle carapace were removed for use as the sample material. The samples are currently undergoing accelerated light aging under three different parameters: exposures mimicking window lighting (which filters some UV), museum lighting (which filters nearly all UV) and a chamber emitting UVA radiation. An important outcome of this research will be a better understanding of photochemically induced alterations in tortoise shell, and preventive lighting guidelines for tortoise shell materials based on the findings of the light aging study.

Piecing together the history of an 18th century printed Armenian Prayer Scroll
Colette Khanaferov

The use of prayer scrolls along with other religious art and literature have for played a significant role in the Armenian culture since the 5th century. The scope of this study is to investigate the history and materials used on a printed, 18th century Armenian prayer scroll. This analysis involves the examination of the scroll with the use of non-destructive analytical photography, fiber optic ultraviolet-visible and near infrared reflectance spectroscopy, X-ray fluorescence and Raman spectromicroscopy. The study attempts to identify and characterize pigments, colorants, ink, and the paper used to construct the prayer scroll. The text along with the illustrations have been translated and studied in an attempt to provide an overall understanding of the scroll, printing techniques, religious significance, use, as well as the traditional practices in the Armenian culture in the 18th century.

Preliminary Research on Biocorrosion of Archaeological Glass
William Shelley

The scope of this research is to investigate the mechanisms and process of biologically induced corrosion of archaeological glass. Archaeological glass samples from Greece and Cyprus suspected to have undergone biocorrosion were analyzed to characterize the chemical composition, microstructure, and topography to determine the difference in the chemistry of the glass surface and the bulk. Analytical techniques included scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray fluorescence (XRF) spectroscopy. Modern glass samples were placed in petri dishes with sulfuric and oxalic acid to simulate potential corrosion from acids produced by microorganisms. This research aims to fill a gap in our knowledge on glass biocorrosion and to evaluate the effects of microorganism on archaeological glass.

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