UCLA/Getty Conservation Program

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


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The Man in the Mirror – a surprising find while cleaning a T’ang style bronze mirror

In the spring of 2016, we had the opportunity to work on a collection of ancient Chinese bronze mirrors from the Ruth Chandler Williamson Gallery at Scripps College, in our course “Conservation Laboratory: Metals I (CAEM 234)” taught by Professor David Scott. I conserved a mirror dated from the T’ang period (618-907 CE) which was heavily encrusted with soil and calcite burial deposits (fig. 1). At first it seemed to be a classic example from that period, with eight lobes and decorated with birds, ribbons and flowers – nothing out of the ordinary. But an unusual feature emerged on the decorated surface during the cleaning process.

mirror-fig1

Figure 1. T’ang period (618-907 CE) mirror before treatment. The decorated side of the mirror is covered with burial deposits such as soil and calcite.

Gradually, a figure of a man, quite literally peeking out from behind one of the flowing ribbons, emerged from under the layers of sand and calcite – his hat, robe, shoes, and beard all visible (fig. 2). The figure was a complete surprise – clearly part of the original casting though in a completely different style and carefully rendered like a tiny line drawing (fig. 3). Amazed that the figure had popped out of the proverbial woodwork (or rather, metalwork), I went back to the x-radiograph taken before treatment, and even there, the figure was nearly invisible – due to a combination of the overall high opacity of the leaded bronze as well as several casting flaws within the metal which helped to obscure small surface variations.

mirror-fig2

Figure 2. Detail of the area on the mirror where the figure was found.

The search began for comparable examples, but so far, after conferring several experts and pouring over online catalogs at other museums, no similar examples have turned up.

mirror-fig3

Figure 3. Drawing of the male figure found on the mirror.

Portable XRF analysis so far indicates that the alloy is within the acceptable ratio of copper, tin and lead for the period. The analysis has also revealed traces of mercury on the mirror-side of the piece, a possible clue that the mirror had been ‘shined’ with tin and mercury – a (non-plating) technique referred to by Zhu Shoukang, He Tangkun, and Nigel Meeks in Metal Plating and Patination: Cultural, Technical and Historical Developments, 1993.

mirror_overlay

Figure 4. Overly of the pXRF spectra collected from the decorated side of the mirror (red) and the mirror side (blue). Mercury (Hg) is present on mirror side but not the decorated side. (Data was collected using the Bruker Tracer SD-III for 900 seconds, at 40kV, 11μA, with a 1 mil Al/1 mil Ti/1 mil Cu filter).

So far, the iconography of this mirror remains a mystery. It is possible it is a later replica made sometime after the T’ang period. With luck and further analysis, the mystery of the “Man in the Mirror” can be further illuminated.

 

Hayley Monroe ’18
This work will be presented at the upcoming 2017 ANAGPIC Conference


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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).

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

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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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Preventive Conservation Education – Research Topics from the Course “Environmental Protection for Collections” (2014)

Faculty from North American conservation programs who are engaged in instructing graduate courses focusing on preventive conservation strategies for collections are sharing curricula, resources, and topics for student research for the first time. With support from the Getty Conservation Institute and a boost from Prof. Hannelore Roemich at the Conservation Center, Institute of Fine Arts, NYU, faculty and alums met in New York in November 2014 to lay the groundwork for these exchanges. The next meeting will take place just prior to the Association of North American Graduate Programs in Conservation annual meeting in April 2015.

Students in the UCLA/Getty Program in the Conservation of Archaeological and Ethnographic Materials, and students interested in collections stewardship from the Department of Information Studies and other fields, together enroll in a course entitled “Environmental Protection for Collections in Museums, Libraries and Archives.” This course involves students in a review of environmental and biological agents of collections deterioration including light, temperature, relative humidity, pollution, and insects and fungi. Students perform monitoring to identify agents and to gain an understanding of material sensitivities and protective methods available for collections. Of increasing significance within all types of collections are preventive, or passive, rather than interventive, or active, methods of preservation. Collections preservation measures are often designed to limit energy use and therefore also contribute to environmental sustainability. In this course, while research topics are proposed for a required paper, students are encouraged to pursue topics that align with their individual interests. What follows are abstracts of research papers completed by students enrolled in the “Environmental Protection for Collections” class during fall 2014.

Student research projects in preventive conservation from the art conservation programs at Queen’s University and the University of Delaware are also accessible. Research from students in other North American programs, as well as curricula and teaching resources, will eventually be made available online.

Map showing one of the spaces monitored in the course this fall (the archives processing room of UCLA's Biomedical Enigineering Libary) and the types and locations of environmental monitoring equipment deployed (map by Heather White)

Map showing one of the spaces monitored in the course this fall (the archives processing room of UCLA’s Biomedical Enigineering Libary) and the types and locations of environmental monitoring equipment deployed (map by Heather White)

Ellen Pearlstein
Associate Professor, Information Studies and the UCLA/Getty Program in the Conservation of Ethnographic and Archaeological Materials


Exhibition of Daylight Fluorescent Colorants
Betsy Burr

When exhibiting collection material, lighting environment must take into account both the fading properties of material and the lighting parameters required for visitors to read the material on display. This can pose a number of challenges when collection material includes fugitive dyes. When modern daylight fluorescent materials are present, there is an added challenge due to the instability of these molecules and the broad spectrum of light potentially required to fully observe their fluorescing properties.  This poses interesting questions regarding the exhibition environment of these pigments as UV filtration is a common method used to preserve material from fading during exhibition. This raises the question of whether UV filters have a noticeable impact on the readability of fluorescent pigments? What properties must be considered in the safe exhibition and storage of daylight fluorescent pigments?

Fluorescent colorants are found on virtually any substrate as dyes, inks, or pigments within a resin or lacquer, and either applied to the surface or mixed into the substrate as seen in plastics. Daylight fluorescent colorants are added to many products today and have been used within fine art since 1960s pop art movement.[1]  They are also found in modern ethnographic works, particularly laundry “bluing” brighteners applied as colorants to traditional materials.[2] These pigments can be found in collections, and as modern material continues to be accessioned into the future, conservators and museum professionals may find an increasing number of collections material including daylight fluorescent colorants.

 

A Brief Discussion of the Photographic Activity Test and its Relevance to Housing Paper Artifacts
Stella Castillo

The Photographic Activity Test (PAT) was developed by the Image Permanence Institute to explore the suitability of housing enclosures for photographic materials and is specifically a predictor of long-term interactions between enclosures and photographs.  The photographic activity test can be performed on paper or plastic and the results of the test indicate whether the enclosures contain harmful chemicals that will cause image fading or staining over time. The test consists of two components: a test to detect image fading resulting from harmful chemicals in enclosures and a test to detect staining reactions between enclosures and gelatin.   The photographic activity test is now an international standard, ISO18916:2007, and is highly regarded as a selling point by manufacturers of archival and storage products.  According to the Image Permanence Institute, the PAT will assist in the elimination of storage materials that may augment destructive consequences that might arise in a less than perfect storage environment.

 

Traditional methods used to enhance preventive protection of paper-based collections from fungal outbreaks
Lesley Day

One of the most dangerous and prevalent problems encountered in collections of paper-based materials is contamination by mold.  Due to the nutritive properties of cellulose for all fungal species, once an outbreak takes root, it can be difficult to contain.  Historically, chemical fungicides have been used in addition to other methods that can be very hazardous to workers due to their toxicity.  These methods are also increasingly known to be hazardous to the collections they are meant to protect, especially paper.  Fungal species are also known to become resistant to chemical fungicides through adaptation, so it is increasingly likely that they will eventually cease to be effective.[3]  An alternative that has started to gain interest in research for the integrated pest management of cultural heritage collections is the use of natural products derived from plant sources such as essential oils or extracts of their active ingredients, medicinal plants, and spices for use in preventive scenarios that also incorporate other measures such as environmental controls.  Research into their use for remedial treatments is also of interest, though so far it has been difficult to find effective applications that do not put objects at risk. This paper will review the research that has been conducted recently about integrating natural methods into pest management for fungal species, and will evaluate an anecdotal account of traditional Indian practices from an Indian conservator and how these methods might be tested for more widespread use in collections.  In addition to preventing harmful exposure to toxic chemicals for both workers and the collections, these methods could find potential applications for culturally sensitive collections that cannot be exposed to chemicals, anoxia, or other methods that would interfere with the cultural significance of the material.

 

Light Emitting Diodes for Libraries
Mitchell Erzinger

Light Emitting Diodes (LEDs) are semiconductor devices that use electrical currents to produce visible light in the form of photons. LED technology has been advancing in recent years, rapidly outgrowing the traditional incandescent and fluorescent light sources to be one of the most cost and energy efficient light sources on the market. This paper will first examine this research into the efficacy of LEDs, citing studies by the Getty Conservation Institute and the U.S. Department of Energy, and following will be a discussion, involving multiple case studies, of the potential benefits of incorporating LEDs into Library settings.

 

Sustainable Selection and the Costs of Light Sources
Kira Fluor-Scacchi

This paper will address the use of LEDs for exhibition lighting in two cooperative definitions of sustainability; the first is that which supports financial stability for an institution, while the second considers this technology as a component of a system which incorporates a social mentality, the physical equipment, and managerial techniques that encourage an environmentally-conscious preservation model. In order for cultural institutions, such as museums, to ensure their long-term sustainability, exhibition factors must be considered that ensure both the viability of the organization as well as the stewardship of significant objects. Museums house and care for these items, and in turn share them with the local community or a community of researchers who value their preservation and accessibility. Policies must be established to allow artworks and artifacts to be displayed in an environment that is suitable to be viewed by patrons while bearing the costs of their exhibition.

 

The Effects of Temperature and Relative Humidity on Digital Photographic Prints
Karen Karyadi

Since its inception in 1839, the field of photography has continued to evolve both aesthetically and technically. The past few years certainly have seen advancements at an exponential rate in this area, especially with the commercial availability of digital photography. Consequently, digitally printed photographs are increasingly becoming the normative output for photographers and artists working with photographic methods. As such, it is important for museums, archives, and libraries, together with the conservation and photographic communities, to be able to address concerns regarding the storage and display of digital prints as part of their role as cultural institutions. Indeed, technological developments in digital photography are taking place on a daily basis and will continue to do so into the foreseeable future—an ongoing shift that must also be anticipated and take into consideration. Nevertheless, this paper focuses on the effects of temperature and relative humidity on digital photographic prints, particularly within the context of cultural institutions.

 

Protecting museum objects from pest infestation and biological growth
Colette Khanaferov

As a visitor it may be hard to conceptualize external factors that can effect a museum’s collection. A museum’s responsibility for the object begins once the object has been acquired into the collection. Conservation of an object however is not limited within the walls of the conservation lab but needs to be considered throughout the entire museum space. Once in the museum, objects are susceptible to pest infestation, biological growth, and deterioration due to fluctuation of temperature and humidity. The scope of this paper is to discuss previous and current approaches taken to eradicate pest infestation and biological growth as well as introduce a potentially new and safer alternative. Chitosan is a naturally occurring polysaccharide that is produced from chitin and can be found in many organisms such as crab shells and shrimp. The use of the polymer includes applications in the food industry as antibacterial agents, in the pharmaceutical field for drug delivery systems as well as new medical advances. Chitin and chitosan can be useful in the conservation field for object preservation.

 

The Physical Implementations in Preserving Fashion Forecasting Reports
Alexander Kosztowny

Archivists, librarians, and historians desire to document, save, and preserve the past. Some ephemera, like newspapers, have an original intent that was not meant to last long periods of time, yet these items are kept and preserved to the best of archivists’ and preservationists’ abilities. One other such example is trend forecasting books and predictive reports. These books are used by the fashion industry to predict what silhouettes, colors, fabrics, and styles will be the most popular in upcoming seasons so designers, manufacturers, and retailers can successfully sell items that consumers want. There is a need to preserve these books in terms of their documenting costume history, popular and street culture, and how the fashion industry has evolved from an elusive, designer based industry to a global communication of style, technology, and individualism. There are many concerns when physically preserving these books that are not unique or unrelated to the preservation of other artifacts and books. However, due to the multimedia nature of trend forecasting reports, many considerations must be taken into account.

 

Illuminative Inhibition of Microbial Growth in Cave Art Systems
Tom McClintock

Several cave systems in France and Spain house some of the earliest known examples of painted surfaces in the world, and since their discovery have attracted major public interest and visitation. The environments of these caves are extreme, characterized by nearly total darkness, stable temperatures, high relative humidity and low amounts of organic nutrients. The organisms that are able to survive in these conditions are highly specialized, and the ecosystems they comprise are subsequently susceptible to change. In this regard, no development of hypogeal environments to accommodate tourism can be considered minor, although the obvious examples of excavation, construction of pathways (even elevators) and installation of air conditioning systems were common practice. When one considers that Lascaux, in Southern France, and Altamira, Spain, two of the most extraordinary cave art sites in the world, hosted respectively 1,800 and 3,000 people per day at the zenith of their visitation[4], [5], the irreversible effect on these delicate systems is hardly surprising. Both Lascaux and Altamira suffered the misfortune of being discovered before management, preservation and scientific communities with an enlightened understanding of these deleterious effects existed, and they must all now play catch up to mitigate the sites’ deterioration.

 

Making Change in Environmental Requirements for Museum Loan Policies
Hilary McCreery

Museum loan policies exist, in part, as a way for museums to ensure that the materials that are loaned out to other institutions will be cared for properly and will return in the same condition in which they departed. One important facet of museum loan policies is the set requirements for museum environments, which establish, among other specifications, explicit levels of temperature and relative humidity to be maintained by the borrowing institution. However, there are many differing perspectives on best practice for implementing standards for museum environments, many of which are based on historical research findings and experience. In fact, “over the past 100 years, both research and practice in the area of environmental standards for storage, loan, and exhibition of museum collections have produced rather bewildering results, from oversimplified formulas to complex, yet incomplete research findings” (American Institute of Conservation, n.p.). Currently, there continues to be much discussion in regards to the rigid parameters set for museum environments, especially in the context of loans, and some conservation and museum professionals have begun to call for a change toward not only more flexible environmental standards, but more transparency on the part of museums about their current practices. As a result, the International Institute for Conservation of Historic and Artistic Works (ICC) in collaboration with the International Council of Museums Committee for Conservation (ICOM-CC) recently released a declaration for new environmental guidelines, which promotes both transparency of and flexibility for environmental conditions in loans policies. While the tight parameters established for environmental conditions in loan requirements have historical roots, the debates taking place in the current landscape of museum policy have called for these new changes in international standards.

 

Bentley’s Medicinal Plants: A Recommendation for Exhibition
Katherine Monroe

Spices, Exotic Flavors & Medicines, a digital exhibition put on by the History Special Collections section of the Louise M.  Darling Biomedical Library at UCLA, incorporates digitized  images  of  the  four  volumes  of  Robert  Bentley  and  Henry  Trimen’s  Medicinal Plants; being descriptions with original figures of the principal plants employed in medicine and an account of the characters, properties, and uses of their parts and products of medicinal  value (hereafter  referred  to  as  Medicinal Plants).[6]  With such an interest in the Internet exhibition,  demand  for  a  twelve month  physical  exhibition  of  the  volumes  has  arisen, leading to an examination of the public reading room in which they are to be displayed, as  well as of the volumes themselves.  The results have led to the following observations and recommendations,  with  the  desire  to  successfully  exhibit  the  four  books  without compromising their preservation.

 

The Use of Experimental Lighting on Archaeological Sites to Prevent Microbial Growth
William Shelley

Microorganisms have the ability to affect archaeological sites not only aesthetically, by covering surfaces with different colored ‘patinas’, but also chemically by producing corrosive acids that attack surfaces.  Methods in the past to control and reduce the growth of microorganisms have included their removal mechanically and the use of biocides.  These techniques however are intended only to remove existing growth and will not prevent future growth.[7]  The use of biocides can be detrimental to archaeological sites if they are not completely rinsed away and leave residues on surfaces.  Biocides may also be toxic to the individual who applies the material, as well as to the environment.  Recently, new strategies to control the growth of biological activity on archaeological sites have been developed using specific wavelengths of light.  A brief overview of previous work on the subject and a discussion about their potential use follows.

 

Environmental Considerations for Alternative Building Materials Used in Museum Storage and Display
Heather White

The materials used for the storage and display of collections play a vital role in maintaining the condition of the collection. Experience has shown that more often than not, traditional building materials contain components that will off-gas harmful vapors, like volatile organic compounds (VOCs), which can initiate or accelerate degradation processes in susceptible cultural materials. Such reactions are promoted by their use and decomposition, especially when subjected to various indoor climate variables. The “indoor chemistry” of building products has been studied in depth, and accounts for reactions that happen during the production of the material whose products are released at the customer’s site, or synergetic reactions between different materials at the site once installed.[8],[9]

Alternative building materials like aluminum composite materials (ACM), entered the market addressing these concerns and offering an inert construction material safe for indoor environments and the collections held within them. However, the question arises: Can such materials so carefully manufactured to be lightweight, strong, weather resistant, water proof, heat resistant, fire resistant, formable, nitrogen/chlorine/sulfur-free, with low VOC emissions, also be safe for the environment at large in terms of their manufacture and disposal? Further, are corporations spearheading the fabrication of safe and archival exhibition cases, like The Small Corporation, maintaining environmentally conscious objectives in their manufacturing processes?

 

Footnotes
[1] Margaret Holben Ellis, Christopher W. McGlinchey, and Esther Chao, “Daylight Fluorescent Colors as Artistic Media,” in The Broad Spectrum (London: Archetype Publication Ltd, 2002), 160–67.

[2] Nancy N. Odegaard and Matthew F. Crawford, “Laundry Bluing as a Colorant in Ethnographic Objects,” in ICOM Committee for Conservation, 11th Triennial Meeting in Edinburgh, Scotland, 1-6 September 1996: Preprints (James & James (Science Publishers) Ltd., 1996), 634–38.

[3] Shaheen Fauzia. 1995. “Application of Kanja Seeds (Pongamia glabra vent) for the control of Museum Insects.” In Biodeterioration of Cultural Property 3: Proceedings of the 3rd International Conference on Biodeterioration of Cultural Property, July 4-7, 1995, Bangkok, Thailand, (Office of Archaeology and National Museums. Conservation Science Division, 1995), pp. 567-575.

[4] Bastian, Fabiola, et al. “Impact of biocide treatments on the bacterial communities of the Lascaux Cave.” Naturwissenschaften 96.7 (2009): 863-868.

[5] Schabereiter‐Gurtner, Claudia, et al. “Altamira cave Paleolithic paintings harbor partly unknown bacterial communities.” FEMS Microbiology Letters 211.1 (2002): 7-11.

[6] The digital exhibition can be accessed at http://unitproj.library.ucla.edu/biomed/spice/index.cfm; Robert Bentley and Henry Trimen, Medicinal Plants; being descriptions with original figures of the principal plant employed in medicine and an account of the characters, properties, and uses of their parts and products of medicinal value (London: J. & A. Churchill, 1880) .

[7] Koestler, R.J., Koestler, V.H., Charola, A.E., Nieto Fernandez, F.E. (Eds), 2003. Art,Biology and Conservation: Biodeterioration of Works of Art. The Metropolitan Museum of Art, New York.

[8] Uhde, E., and T. Salthammer. “Impact of reaction products from building materials and furnishings on indoor air quality—A review of recent advances in indoor chemistry.” Atmospheric Environment 41 (2007): 3111-3128.

[9] Satlhammer, Tunga. “Emissions of Volatile Organic Compounds from Products and Materials in Indoor Environments.” The Handbook of Environmental Chemistry 4, Part F (2004): 37-71.


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Examining Plant Fibers and Identifying Characteristic Features using Microscopy

Last quarter in the class Structure, Properties and Deterioration of Organic Materials (CAEM 262), we completed practical assignments in order to understand how to identify and approach organic materials found within and comprising cultural objects.  Each week the class studied a different category of organic materials including wood, paper and bark cloth, other plant materials, skin and leather, bone and ivory, plastics, and hair, quills and feathers.

During our study of plant fibers, we utilized light microscopy, both with transmitted and polarized light, to view and identify fibers and diagnostic features of plants that could help in identification and documentation of materials used in the manufacture of objects.  Different types of plant tissues and fibers can be used to produce a range of materials including cordage, baskets, paper, and native or conservation mends.  The processing method of fibers may also be seen, and commercial fibers can usually be identified by their absence of impurities or extraneous material.   An important reason for identifying plant materials is to understand their current state and how they may deteriorate in the future due to their inherent properties. By studying and identifying the materials of which an object is made, as conservators, we will be to make more informed decisions about conservation treatment, repairs, stabilization and storage (Florian et al. 1990: 29).

Using the UCLA/Getty Program’s vast reference collection of plant materials, each student chose and mounted on a microscope slide a surface section of a seed hair (fibers that surround plant seeds, like cotton or kapok), a surface section of a bast fiber (fibers harvested from woody stems, like flax or hemp), a cross-sectional sample of a monocot leaf (like palm) and a cross-sectional sample of a monocot stem (like a grass).  We then took photomicrographs of our samples and labeled the features that could be identified.  Features that we were hoping to observe included tissue organization, cellular structure and details, and birefringent patterns and colors.   Below are the photomicrographs obtained using and Olympus BX51 microscope with transmitted and cross polarized light by Lesley Day, William Shelley and Betsy Burr.

 

Seed Hair Surface Sections

Polarized Light Microscopy (PLM) is very useful in identifying cotton and other seed hairs.  Cotton characteristically shows ribbon-like twists and birefringence.  Cotton hairs are single cells that originate from the fruit or boll of the cotton flower.  Other seed hairs such as kapok and cattail characteristically show few to no features, and lack of features can help in their identification (Florian et al. 1990: 40). Samples were prepared by teasing out a small amount of material and placing it on a glass microscope slide.   A drop of water was placed on the fiber and covered with a plastic cover slip.

Image: Lesley Day

Image: Lesley Day


Image: William Shelley

Image: William Shelley


Image: Betsy Burr

Image: Betsy Burr

Bast Fiber Surface Sections Bast fibers are long thick-walled cells harvested from the inner bark of hardwood trees.  They are commercially and culturally important because they are used in cordage, basketry and paper.  Flax and hemp are examples of bast fibers and are harvested from the stems of dicots.  Salient features used to identify bast fibers are dislocations (also called kinks), long length, tapered ends and narrow lumens.  The fibers usually occur as clusters, and the presence of single fiber ultimates may indicate more extensive processing (Pearlstein, lecture 28 January 2014). Samples were prepared in the same manner as above.  In some instances, the samples were macerated in order to separate fiber bundles for better viewing of fiber ultimates, by gently applying pressure in a circular motion to the coverslip with a pencil eraser.

Image: Lesley Day

Image: Lesley Day


Image: William Shelley

Image: William Shelley


Image: Betsy Burr

Image: Betsy Burr

Cross Sectional Sample of a monocot leaf Monocot leaves from palms and grasses are commonly used culturally in the weaving of baskets and other structures.  The leaves are quite strong due to the parallel veins and the strengthening sclerenchyma and vascular bundles corresponding to them.  A waxy cuticle is present on the exterior, which contains natural, water repellent waxes, and is often removed during processing.  Observable characteristics of monocot leaves include the epidermis, vascular bundles (which include xylem and phloem cells), sclerenchyma bundles, and occasionally stomata, which are tiny mouths that permit transpiration (Pearlstein, lecture 28 January 2014)! Samples were prepared by cutting a very thin slice from the end of a monocot leaf using a scalpel and carefully placing the sample on a glass microscope slide so that the cross section faced up. Once the sample was in the correct orientation, a drop of water was placed on the area around the sample and a plastic cover slip was placed on top.

Image: Lesley Day

Image: Lesley Day


Image: William Shelley

Image: William Shelley


Image: Betsy Burr

Image: Betsy Burr

Cross-sectional sample of a Monocot Stem Monocot stems are also used in basket weaving and stems are obtained from grasses, sedges, rushes, and palms.  Monocot stems do not develop bark on their exteriors and do not exhibit growth rings. Identifying features observable in a cross-sectional sample include the outer cortex, vascular bundles (in which phloem, xylem and cambium may be visible), epidermal cells, and sclerenchyma bundles (Pearlstein, lecture 28 January 2014). Samples were prepared by cutting a very thin slice from the end of a monocot stem using a scalpel and carefully placing the sample on a glass microscope slide, followed by a drop of water and a cover slip.

Image: Lesley Day

Image: Lesley Day


Image: Lesley Day

Image: Lesley Day


Image: William Shelley

Image: William Shelley


Image: Betsy Burr

Image: Betsy Burr

In addition to taking really beautiful and informative photomicrographs, students gained valuable experience with sampling techniques.  The challenges of isolating single fiber ultimates or obtaining good cross sections on the reference materials, illustrated that much experience and care are necessary when taking samples from actual artifacts.  Once students were able to see the differences between features, locating them without sampling was possible in some cases!   

References Florian, Mary-Lou E., Dale Paul Kronkright, and Ruth E. Norton. The Conservation of Artifacts Made from Plant Materials. Getty Publications, 1991. Pearlstein, Ellen (2014). Other Plant Materials, Lecture in Structure, Properties and Deterioration of Organic Materials, UCLA, Los Angeles, CA, January 28th , 2014.  

by Lesley Day (’16)


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Tight, Aligned Joins Does Not a Sprung Vessel Make

In our first quarter class, CAEM 260: Structure, Properties, and Deterioration of Ceramic, Glass and Glazes, we were assigned a ceramic object on loan from  Southwest Museum of the American Indian Collection, Autry National Center to examine, document, and treat the following quarter. I was given a low-fired, light-colored Chiriqui vessel whose largest condition issue was its fragmentary state; the vessel was in 5 large fragments with additional small pieces in an accompanying bag (Fig. 1). As I would soon learn, assembling a broken vessel is not simply putting a puzzle back together and finding which pieces go where. The stress released as a vessel is broken can result in fragments that don’t quite meet up to complete the object as it was before—and I learned exactly how frustrating it can be to achieve tight and aligned joins with stubborn objects like this!

Fig. 1. A soon-to-be joined Chiriqui vessel, comprised of 5 large fragments and several small pieces.

Fig. 1. A soon-to-be joined Chiriqui vessel, comprised of 5 large fragments and several small pieces. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

Joining my vessel (with 40% Acryloid B-72 in acetone using a brush) went quite well in the beginning, such as with Fragments C and E  (Fig. 2).

Fig. 2. Fragments C and E prior to joining (a) and after joining (b); the resulting join was tight and aligned (c).

Fig. 2. Fragments C and E prior to joining (a) and after joining (b); the resulting join was tight and aligned (c). Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

I determined the best sequence would be to join Fragments C-E-A and Fragments B-D (Fig. 3).

Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

These two sections would then come together to complete the vessel…however this didn’t prove to be as easy as I had thought. I found that while one side of the join was well aligned and tight, the other side by comparison was like a mile-wide fissure as far as I was concerned (Fig. 4); a jolting discovery for a newbie in training! The two sections just didn’t fit, despite careful and tight joining of the fragments that comprised them.

Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

Any ideas I had about merely adding adhesive and piecing the vessel back together were naively simple and optimistic in hindsight, but fortunately lab manager and conservator, Vanessa Muros, was able to guide me through a more complicated (and at times scary!), multi-stage aligning method involving heat and pressure. The misaligned fragments were adjusted using a hair drier (set to a low temperature) to soften the B-72, and then pressure was applied using 3M Coban self-adherent wrap and soft-grip clamps, with barriers of thin Ethafoam and Volara (Figs. 5-6); slow tightening of the Coban wrap was performed regularly using a wooden popsicle stick. This process may seem simple, but pressure was required in multiple directions and aligning one area often caused another to move and misalign; all joins had to be considered. It became a battle over control between what I wanted the fragments to do and how they naturally wanted to be, all while gauging the safety of the object and determining when enough was enough.

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Figures 5-6.  Alignment of the joins. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

Figures 5-6. Alignment of the joins. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

In the end, relatively good joins were achieved overall (Figs.7-8). The changes that occurred from the stress released upon breaking still prevented perfectly tight and aligned joins everywhere, but the best compromise was achieved and the results were more than satisfactory. I was able to learn about the unforeseeable problems that can occur during the treatment of ceramics, and I gained a greater feel for the material and how it behaves…and I’ll be ready for the next one!

Fig_7_HWhite_Blog_Post

Figures 7-8.  Vessel after treatment. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

Figures 7-8. Vessel after treatment. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

by Heather White (’16)


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Conserving Nayarit Ceramics

Last quarter we both had the opportunity to treat pre-Columbian Nayarit ceramic figurines from Mexico, on loan from the Southwest Museum of the American Indian Collection, Autry National Center. At first glance we thought the treatment would be pretty straightforward, but after a closer look it appeared to be anything but!

The surface and structure of the figurines are deceptively highly restored, which can be common for artifacts passing through the art market. In addition to reassembling the fragmented figurines, our goal is to document and identify old from new, and shed light onto the unknown pasts of these objects. We’re approaching the project with a range of tools including X-ray imaging, UV-induced visible fluorescence imaging, X-ray diffraction (XRD) analysis, and X-ray fluorescence (XRF) spectrometry. XRF analysis indicates the presence of lead and zinc on the surface of both figurines, which are common in modern pigments, though typically not found in pre-Columbian ceramics. Using XRF and XRD, we also detected the presence of plaster in some areas, a common restoration material for ceramics. While we work to try to piece our puzzles together, take a look at our projects!

Female Nayarit figurine before treatment. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; [2232.G.33]

Female Nayarit figurine before treatment. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.33

Female Nayarit figurine during treatment: after reconstruction (left) and after gap-filling of the joins to stabilize fragments on the nose and lower section of the body (right). Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.33

Female Nayarit figurine during treatment: after reconstruction (left) and after gap-filling of the joins to stabilize fragments on the nose and lower section of the body (right). Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.33

Female Nayarit figurine after treatment. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.33

Female Nayarit figurine after treatment. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.33

Figure 5: Male Nayarit figurine, imaged under visible light (left), 415 λ induced visible fluorescence (center) and B&W image of UV induced visible fluorescence (right). Fluorescence imaging can help distinguish difference in material that cannot be detected under normal lighting conditions.  It is common for restoration materials to fluoresce distinctly from original material. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.28

Figure 5: Male Nayarit figurine, imaged under visible light (left), 415 λ induced visible fluorescence (center) and B&W image of UV induced visible fluorescence (right). Fluorescence imaging can help distinguish difference in material that cannot be detected under normal lighting conditions. It is common for restoration materials to fluoresce distinctly from original material. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.28

 X-ray image of Male Nayarit figurine taken from the back of the object at 45 kV.  This imaging technique reveals that the body is composed of many fragments that have been previously restored. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.28

X-ray image of Male Nayarit figurine taken from the back of the object at 45 kV. This imaging technique reveals that the body is composed of many fragments that have been previously restored. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.28

XRF analysis was conducted on the rear supports at the bottom of the figurine.  The spectrum shows presence of gypsum-based plaster due to the high calcium peak (CaKa1) and presence of a sulfur peak (S Ka1) indicating this is an area of restoration.  The significant amounts of titanium (Ti Ka1) and manganese (Mn Ka1) may be from modern pigments used to paint the plaster surface.

XRF analysis was conducted on the rear supports at the bottom of the figurine. The spectrum shows presence of gypsum-based plaster due to the high calcium peak (CaKa1) and presence of a sulfur peak (S Ka1) indicating this is an area of restoration. The significant amounts of titanium (Ti Ka1) and manganese (Mn Ka1) may be from modern pigments used to paint the plaster surface. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 2232.G.28

Colette Khanaferov and Betsy Burr (’16)


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Hammering Away in L.A.

On Tuesday, Professor Scott took us on a field trip to visit Dr. Arik Greenberg’s metal studio. Dr. Greenberg is a lecturer of Greco-Roman history and religion and has been involved with the Legion Six Historical Foundation, Inc. and the development of the Museum of the Ancient Roman Soldier.

Dr. Greenberg first gave us a presentation on Greco-Roman armor and weaponry.

1lesson on armor

We dressed Tom McClintock up as a soldier with replica armor, a shield, and a sword.

3tom solider

Dr. Greenberg then gave us a demonstration on the manufacturing of ancient copper helmets and iron swords, showing us different blacksmith forging techniques.

7arik remvoing metal from furnace 8arik hammering layers together

9after first hammering layers starting to combine

We then had the opportunity to work our own copper sheets into a bowls, which involved annealing and hammering. Lesley Day (left image) cools the metal she is working after annealing. Betsy Burr and Lesley (central image) hammer their copper sheets into shape. And Tom (right image) anneals his copper sheet.

5leslie cooling metal after annealing 6hammering into a shape 4annealing

The field trip was part of the course we are taking this quarter on the Technology and Deterioration of Metals (CAEM 263). Not only was our visit to Dr. Greenberg’s metal studio fun, but seeing how metals are worked, and trying our hand at making copper bowls, will help us better understand how the copper alloy objects we’re examining this quarter (and treating next quarter) were made.

I’ll end this post with the words of MC Hammer, because for us in the metal’s studio, it was definitely “Hammer Time”.

William Shelley (’16)