Radical Ideas or New Directions for AIC?

May 11, 2009

Thanks, Ellen, for letting me write a guest post on your blog.  The amount of conservation information you’re sharing here is impressive; I really can’t think of anyone who is putting as much treatment and research information out as you.  It’s as if you’re running your own conservation publication for the state of Alaska!

Also, I think it’s fascinating that you and I can be connected in a meaningful way without having met in person or chatted on the phone.  After all, you’re way up there in Alaska, and I’m here in Indianapolis.  To make this point visual, my friend, Tascha, in the IMA Photography department, made the image below.

Richard's Indianapolis Blog Cruise Stops in Alaska

Richard's Corn-Fed Blog Cruise Stops in Alaska

In recognition of the upcoming AIC Annual Meeting being held in Los Angeles that is dubbed “Conservation 2.0 — New Directions,” I thought it would be a good idea to put out some thoughts on “New Directions.”  Following this post, on Wednesday Ellen will be posting over at my home blog at the IMA and then on Friday Daniel Cull will posting at The Dan Cull Weblog.  We’ve all agreed to address potential “New Directions” for AIC.

Of course, to me, it makes total sense that I publish this post here in Alaska.  In many ways I think it is projects like Ellen’s blog that are beginning to change the landscape within the conservation profession and point to new directions.  I’m not just talking about starting a blog and telling people what you do, but it’s the capacity for anyone in the world to use a very powerful printing press basically for free.  The ability to share information about art conservation is changing dramatically.

Read the rest of this entry »


The Influence of Early Ethnographic Conservation in Alaska

April 3, 2009

The Objects Specialty Group Postprints. Vol. 10 Proceedings of the Objects Specialty Group Session.   American Institute for Conservation 31st Annual Meeting, Arlington, Virginia. June 8, 2003. 

The Influence of Early Ethnographic Conservation in Alaska.

By Scott Carrlee and Ellen Carrlee

*note: 2009 update at the end

 

The state of Alaska spans a terrain as wide as the continental U.S. and occupies one-fifth the landmass of the lower 48 states, yet contains a population only slightly larger than the District of Columbia.  Almost 60% of these people live in the three largest cities: Anchorage, Fairbanks, and Juneau.  The struggles of a small population in a vast land have always colored the history of the state.  Isolation has always been an important factor in the geographic and cultural development of Alaska.  A visitor behind the scenes in many small, remote Alaskan museums may be surprised, however, to find unusually good collections care, awareness and respect for preventive conservation, a long history of contact with conservators, and a sophisticated attitude toward the role of the museum in the community.  Certain key events contributed to those successes.

Civic consciousness paired with financial boom times influenced museum development in Alaska in the second half of the 20th century.  When statehood came to Alaska on October 18, 1959, there were only six museums in Alaska.  In 1967, the Purchase Centennial celebrated the bargain once called “Seward’s Folly.”  Alaska was purchased from Russia in 1867 for $7.2 million, the equivalent of $84 million today.  A federal block grant to the State of Alaska Purchase Centennial Commission was distributed throughout the state for community projects.  Many communities identified a need for local museums, and the number of Alaskan museums doubled during the events surrounding the centennial celebration.  In 1968, oil was discovered on the North Slope.  Construction began on the oil pipeline in 1974, and by 1975 the economy of state had doubled.  The first oil was pumped in 1977.  The Alaskan Canadian Highway (often called the Alcan Highway), built during WWII by the Army Corps of Engineers in response to Japanese attacks on American soil, underwent upgrades and improvements in the 1970s to support pipeline construction.  Improvements led to a boom in adventure tourism as well as opening up the interior to further settlement.  Alaska’s population grew by a third during that decade.  The 1976 United States Bicentennial celebrations raised national consciousness about history and the importance of preserving artifacts.  Many museums nationwide began to implement preservation policies and hire conservators.  Cruise ship tourism in Alaska was steadily on the rise in the 1980s, but exploded in the 1990s as a result of the Gulf War and American fears of traveling abroad.  By the end of the decade, tourism in the state increased by threefold.  

Today there are more than 60 museums and cultural centers in Alaska.  Even with the advent of “industrial tourism” the typical small Alaskan museum struggles to keep its doors open.  Admission tickets pay for only a fraction of the operating expenses, and the meager staff are often unpaid volunteers.  Professional training is rare.  The exhibits of these small museums can be hard to distinguish from the curio shops on every town’s Dock Street, hawking pseudo-Alaskan antiques and featuring bear skins and moose antlers on the walls.  Old-fashioned museum cases are over-filled with artifacts and memorabilia, often with a yellowed label typed on an index card.  

Behind the scenes, however, collections care, with an emphasis on preventive conservation, is surprisingly up-to-date.  Shelves are lined with closed-cell polyurethane foam, windows and lights have UV filters, gloves are worn, and objects tend to be securely housed.  The staff generally understands conservation and has specific ideas about what a conservator can do for them.  Indeed, 15 museums in Alaska (nearly 25%) have had Conservation Assessment Programs to date.  In 1990, during her time as conservator at the Alaska State Museum, Helen Alten conducted a conservation survey of the state.  She noted that over half the museums which responded had been visited by a conservator.  Over 80% stored their collections in acid-free materials and nearly 90% regularly sought conservation and preservation advice from the Alaska State Museum.  Today, there appears to be a unified conservation philosophy among the small museums of Alaska.  It is based on good fundamental collections care, preventive conservation and contact with professional conservators for advice and treatment when necessary.  This is remarkable, considering a grand total of only four conservators ever held permanent positions in Alaska before the year 2000.  What is the origin of this preventive conservation legacy?  Why did it stick so well in these museums?

The first big wave of conservation appears to have hit Alaska in the year 1975.  Bethune Gibson, head of the Smithsonian’s Anthropology Conservation Lab, was invited to the Sheldon Jackson Museum in Sitka to perform what seems to be the first general conservation survey done in the state.  Her report outlined the basic conservation condition of the collection, illuminated the environmental factors that were creating problems, and made recommendations for improvements.  It appears likely that her report, and the connection with the Smithsonian’s Anthropology Conservation Lab, led to the grant obtained by the Sheldon Museum to hire Toby Raphael as an ethnographic conservator for three months in the summer of 1975.  Raphael was studying at the George Washington University ethnographic and archaeological training program headed by Carolyn Rose, and internships at the Anthropology Conservation Lab were part of the program.  

Conservation treatments carried were carried out in a makeshift lab in the staff lounge of the Sheldon Jackson college library.  In his report at the end of the summer, Raphael noted that a large percentage of his time was devoted to the Eskimo mask collection since it was considered one of the most valuable in the museum.  

During the same period of time, one Alaskan was becoming increasingly interested in preserving collections.  Mary Pat Wyatt was the Curator of Collections at the Anchorage Museum of History and Art.  She was also working on a master’s thesis, “Problems in Conservation of Alaskan Ethnographic Material,” when she met Smithsonian conservator James Silberman.  Silberman was traveling with the “Far North” exhibition, a large exhibit covering 2,000 years of Eskimo, Indian, and Aleut culture that had been organized by the Smithsonian Institution.  He encouraged Wyatt to pursue an internship in conservation at the Smithsonian.  She contacted Bethune Gibson and organized an internship year at the Anthropology Conservation Lab starting in August of 1975.  This internship at the Smithsonian formed the backbone of her conservation education.  Wyatt returned to Alaska in 1976 to take a nine-month conservation position at the Alaska State Museum funded by the National Endowment for the Arts.  This was the first conservation position at any Alaskan museum, and remains the only conservation position in any institution in Alaska, despite the fact that both the University of Alaska Museum at Fairbanks and the Anchorage Museum of History and Art have considerably larger collections.  

Wyatt converted a darkroom in the basement of the Alaska State Museum in Juneau into a conservation laboratory and even managed to find a fume hood that is still in operation today.  Her primary concern, however, was outreach.  She visited 15 museums and cultural agencies around the state where she gave presentations and workshops on general collections care.  The following year the conservation position continued to be funded with another grant from the National Endowment for the Arts as well as a National Museum Act grant.  The focus of the lab continued to be statewide outreach.  Museums and cultural agencies around the state were invited to send objects to objects to Juneau for conservation treatment.  Three regional workshops were held in Juneau, Fairbanks, and Homer with a total of 68 participants.  Topics covered included grant writing, exhibits development, collections care, and preservation.      

In 1977, John Turney of the Valdez Heritage Center met Matilda Wells of the National Museum Act, who put him in touch with Caroline Keck of the Cooperstown Graduate Program in Conservation.  Arrangements for student interns to work in Alaska were discussed, but did not materialize.  

In the summer of 1978, four graduate students from the George Washington University/ Smithsonian Conservation program came to Alaska to do conservation work.  The National Museum Act provided the funding and Mary Pat Wyatt coordinated the work.  The four conservators were Alice Hoveman, Melba Myers, Susan Paterson, and Thurid Clark.  They worked in teams of two at four museums for one month each.  The four museums were the University of Alaska at Fairbanks, the Baranov Museum on Kodiak Island, the Sheldon Museum in Haines, and again the Sheldon Jackson Museum in Sitka.  In addition to treating the objects most in need of conservation at each museum, the teams also wrote reports providing recommendations for general conservation care of the collections.  The communities were impressed with the Smithsonian conservators, and there was local press coverage of the projects.  One of the students, Alice Hoveman, returned to Alaska after graduation to volunteer her time at the Sheldon Jackson Museum in Sitka.  The following year, Hoveman would take the position of Conservator at the Alaska State Museum following the departure of Mary Pat Wyatt.  Wyatt returned several years later to become the curator at the Juneau-Douglas City Museum, as position she held for almost 20 years.  

The State Conservator position was financed through grants until 1980, when a permanent full-time position was funded by the Legislature.  The nascent Conservation Services Program also had political implications.  Juneau was constantly striving to prove itself of service to the rest of the state in order to fend off attempts to move the capital closer to Anchorage.  Statewide outreach became a major mission of the Alaska State Museum.  Alice Hoveman presented a talk at the 1981 American Institute for Conservation Services Program.  According to Hoveman, 

“There existed a serious lack of understanding concerning preventive care for collections; i.e., inadequately controlled environments, limited security, and improper handling, storage, and exhibit techniques.  These conservation problems are complicated by the physical isolation and remoteness of Alaskan museums and the limited financial resources many Alaskan museum personnel are faced with.” (Hoveman, 1981)

The approach included on-site assessments, environmental monitoring kits and conservation literature available on loan, assistance for emergencies and disasters, and individual treatments for objects stable enough to be shipped to Juneau.  Hoveman also initiated the Museum Wise Guide, a booklet about collections care for Alaskan materials which included appendicies listing conservation suppliers and conservation-related organizations.  This booklet, funded by a grant from the Institute of Museum Services, has been distributed free of charge to Alaskan museums and cultural centers since 1985.  It is now in its revised second printing funded by the Institute for Museum and Library Services and is available on the internet.  Alice stayed in the position until February 1987, when Helen Alten took the position.  

In advertising jargon, people speak of certain campaigns having “legs,”  meaning that they achieve a longevity that goes beyond the initial appearance of the message in the media.  The conservation message that was carried by the core group of early ethnographic conservators in Alaska had “legs.”  The message seems to have gotten through and stuck with many of the smaller museums that had early conservation contact.  The message was carried on even with numerous staff changes.  We may never know why this is so, but a few ideas can be postulated.  

First, all of the early conservation participants during the formative years were trained at the same place, the George Washington University program led by Carolyn Rose, and/or the Anthropology Conservation Lab at the Smithsonian.  Second, the message was simple and effective.  It emphasized preventing damage and the fundamentals of good collections care, not the treatment of artifacts.  The concepts presented were meant to be understood by staff without specific conservation training.  Indeed, it may be that the museum workers lacking professional training were more receptive to this message.  Some of the larger, better-funded institutions in the state have not made conservation a priority, even today.  Third, the plans and recommendations could be carried out in the absence of continual conservator input.  The conservators came, but no one knew when they might return.  

Ethnographic conservation at its core is neither an art nor a science but rather a philosophy.  It is a philosophy firmly rooted in preventive conservation, and distinct from traditional fine arts conservation that is rooted in individual treatments.  The ethnographic conservators who studied at the George Washington/Smithsonian program were trained to care for large and diverse collections, to do the most good for the most artifacts with the resources available, and to look at the big picture before considering individual treatments.  

According to the National Needs Assessment Survey conducted by IMS in 1992, 75% of U.S. museums had a budget under $250,000 and are defined as small museums.  Most of these museums, like those in Alaska, do not have a conservator on staff.  Yet these museums house the majority of our cultural heritage.  Individual conservation treatments save individual pieces, often the spectacular and priceless ones.  But for the bulk of our historical material, it is the unspectacular realm of preventive conservation that will carry our treasures, great and small, into the future.  

Richard Beauchamp spoke at a museum workshop in 1976.  In his talk, he quoted Canadian conservator Phil Ward, and the words have great strength today as well: “Only the material specimens of humans and natural history are indisputable; they are the raw materials of history, the undeniable facts, the truth about our past.  Conservation is the means by which we preserve them.”

REFERENCES

Alten, H. 1993.  Results of the 1990 Alaska State-wide Conservation Survey.  Western Association of Art Conservators Newsletter.  15(3): 29.

Alaska State Museum.  1984.  Alaska Museums in the 80s: a Profile.  Juneau: Alaska State Museum.  

Beauchamp, Richard.  1996.  Unpublished talk delivered at the Museum Institute, Alaska State Museum, Juneau.  

Hoveman, A.R. 1981.  The Alaska State Museum Conservation Services Program.  American Institute for the Conservation of Historic and Artistic Works preprints of the papers presented at the ninth annual meeting Philadelphia, Pennsylvania, 27 April- 3 May, 1981.  Washington D.C.: American Institute for Conservation. 82-85.

Hoveman, A.R. 1985.  The Conservation Wise Guide.  Juneau: Alaska State Museum.  

Institute for Museum Services. 1992.  National Needs Assessment of Small, Emerging, Minority and Rural Museums in the United States.  A Report to Congress, September 1992.  Washington D.C.:  U.S. Government Printing Office.  

*UPDATE 2009

There are now thought to be closer to 80 museums and cultural centers in Alaska.  Some are new, and some small ones are just lately coming on the radar of outreach services at the Alaska State Museum.

Additional CAP assessments have been done in Alaska, perhaps at the rate of 2-3 per year, making he percentage of museums with assessments closer to 30% in 2009.

ADDITIONAL ETHNOGRAPHIC CONSERVATION INFLUENCE SINCE THE 2003 ARTICLE:

2001-2003? Melinda McPeek (2000-2001 Pre-program conservation intern, National Museum of the American Indian when Scott Carrlee and Ellen Carrlee had worked there) Museum of the Aleutians, Unalaska. Collections Manager.  Educational background in anthropology and art history, continued on in the museum field as a collections manager with an ongoing interest in conservation.

2002 Lara Kaplan (student, University of Delaware/Winterthur Conservation Program) Sheldon Jackson Museum, Sitka.  Birchbark canoe project, summer internship.

2001-2004? Sean Charette (don’t know his full conservation background, seems he went on to do work at the Getty and the Freer/Sackler) Museum of the Aleutians, Unalaska. Collections Manager.

2004 Dana Senge (student, Buffalo State Conservation Program) Yupiit Piciryarait Cultural Center and Museum, Bethel.  Collection care project, summer internship.

2007 Dana Senge (2006 graduate of Buffalo State Conservation Program) Baranov Museum, Kodiak.  Baidarka treatment project.  Sole proprietor, DKS Conservation in Seattle.

2007 Janelle Matz (2007 graduate of the University of Northumbria Preventive Conservation Program) Manager of the Contemporary Art Bank for the Alaska State Council for the Arts beginning in 2007. Had long been a collections manager at the Anchorage Museum, and had done some conservation treatments there as part of her work.   Had some early formal training…perhaps a Smithsonian internship?  Sole proprietor of ArtCare?

2007 Dana Senge (2006 graduate of Buffalo State Conservation Program) Baranof Museum, Kodiak.  Baidarka project.  Two weeks in March. Sole proprietor, DKS Conservation in Seattle.

In 2007, the Anchorage Museum of History and Art established a conservation position.  It was filled by Monica Shah, who grew up in Anchorage and received a Master’s of Science degree from the University of Delaware/ Winterthur Museum conservation training program in 1999 with a specialization in Ethnographic and Archaeological Objects.  Prior to accepting the position, Monica had run a private conservation business in Anchorage for several years.  In summer 1998, Monica, Ellen Carrlee, and Scott Carrlee all worked together in the lab of the Smithsonian’s National Museum of the American Indian in the Bronx, New York.

2007 Molly Gleeson (student, UCLA/Getty Museum Conservation Program) Alaska State Museum, Juneau and Sheldon Jackson Museum, Sitka. Basketry project.  Summer internship, presented paper at 2007 ICOM-CC Triennial in New Delhi, co-written by Samantha Springer, Teri Rofkar and Janice Criswell; also presented at the 2008 AIC conference.

2007 Samantha Springer (student, U. of Delaware/Winterthur Conservation Program) 2007 ASM, Juneau. Alaska State Museum, Juneau and Sheldon Jackson Museum, Sitka. Basketry project.  Summer internship, presented paper at 2007 ICOM-CC Triennial in New Delhi, co-written by Samantha Springer, Teri Rofkar and Janice Criswell; also presented at the 2008 AIC conference.

2008 Dave Harvey (apprentice trained, Professional Associate in AIC) Assessment of the Rapuzzi Collection for the National Parks Service.  Several days in fall 2008.  At the time, worked for Griswold and Associates in Los Angeles. 

2009 Jennifer Dennis (student, Buffalo State Conservation Program) Baranov Museum and the Alutiiq Museum in Kodiak.  Summer internship.

INTERESTING BUT NOT ETHNOGRAPHIC

1992 Vera Beaver-Bricken Espinola advised on treatment of Russian Icons in the Aleutians?  Published biography indicates she received a B.I.S. in Russian studies from George Mason University and an M.A. in museum studies with a concentration in ethnographic and archeological object conservation from George Washington University. She interned in the Anthropology Conservation Laboratory of the Smithsonian Institution. Fluent in Russian, she received an International Research and Exchanges Board (IREX) grant to study Soviet conservation techniques in Moscow, Novgorod, and Leningrad in 1980. A conservator in private practice in St. Petersburg, Florida, she has worked for museums such as the Smithsonian Institution, Hillwood, and the Timken Gallery, and for churches and private collectors as well as on exhibits, legal, insurance, and environmental problems concerning Russian icons and objects.

1998-2008? Cynthia Lawrence. Icon restoration project of Pribolof Islands, funded through restitution money from department of defense?

2001 John R. Kjelland (AIC member, in business as a furniture conservator since 1972.) Worked on the 46-foot historic Brunswick bar at the Valdez Museum.

2003-2007 Emily Ramos (1992 Library Conservation degree from Columbia University) Private conservation business in Anchorage, mainly working with the Rasmuson Library & Archives at Anchorage Museum. Managed the Contemporary Art Bank for the Alaska State Council for the Arts from 2005-2007.  Left Alaska for the job at the University of Berkeley Library system in 2007.2005 Tram Vo (2001 graduate of U. of Delaware/Winterthur Conservation Program) working at the UAF archives with Ann Foster to do an assessment of their photo collection.  Tram Vo Art Conservation, Los Angeles.

2009 Jennifer McGlinchey (student, Buffalo State Conservation Program) specializing in photographs, working with the Alaska State Historical Library and Alaska State Archives, also to travel around the state as part of  ARC (Archives Rescue Corps) and ASHRAB (Alaska State Historic Records Advisory Board) Summer internship.

2009 Grace White (2002 MA paper conservation, Northumbia University, England) Worked at Eagle Historical Society, UAF, and Barrow February-March 2009 to gain experience for Antarctica.


Summary of Potential Artifact Damage from Low Temperature Pest Control

April 3, 2009

The Textile Specialty Group Postprints: A Joint Session with the Objects Specialty Groups Concerning Composite Objects.  American Institute for Conservation 30th Annual Meeting Miami Florida, June 2002.

 

Summary of Potential Artifact Damage from Low Temperature Pest Control

 

Abstract

Preventive freezing for pest control during the relocation of the ethnographic collection of the Smithsonian Institution’s National Museum of the American Indian, Suitland, MD afforded the opportunity to undertake an observational study of the potential damage to vulnerable categories of materials and to investigate the possible causes.  The observational study revealed no visible damage to any of the materials frozen, although minor changes on a molecular level are likely.  Moisture issues are less of that threat than effects related to low temperature alone, such as shrinkage, embrittlement, and molecular alteration.  While many of these changes are reversible upon warming, the danger of cumulative effects from repeated preventive freezing of objects is questioned.  The conservation tradition of borrowing information from other fields proves difficult to apply to a low-temperature low-moisture content closed system.  This study contributes to an informed approach for the freezing of composite objects, cracked objects, lamellar objects, and waxy or oily objects.  Concepts of condensation, moisture content, concentration effects, glass transition temperature, coefficient of thermal expansion, polymorphism, lipid autoxidation, protein denaturation, ratcheting and shakedown are reviewed.  

 

INTRODUCTION

The Smithsonian Institution’s National Museum of the American Indian (NMAI) is in the process of moving its collections from facilities in the Bronx to the new Cultural Resources Center in Suitland, MD, just outside of Washington DC.  The old facilities had many insect infestations, and the current move protocol includes preventive low temperature treatment of most organic materials before entering the new facility.  Objects are sealed in a close-fitting polyethylene bag with padding and cooled below -20C for at least five days.  This situation afforded the opportunity for an observational study of the potential changes to ethnographic artifacts from low temperature pest management.

 

BACKGROUND

Several categories of artifacts are thought to be cause for concern at low temperatures.  One category is composite objects.  Materials generally not exposed to low temperature treatments, such as glass and metal, may be attached to materials appropriate to treat, such as wool.  Composite objects may also have built-in tension, and one material may restrict the movement of a different material.  A second category is cracked objects.  Concern here lies in possible propagation of the cracks or potential structural weaknesses implied by the presence of cracks.  Delamination of lamellar objects is another area of concern.  Examples include tooth and horn as well as layered constructions such as painted wood or adhesive systems.  The fourth category includes oily or waxy objects which sometimes demonstrate bloom or crystallization.  

 

DISCUSSION

The possible causes of artifact damage divide into those related to water and those not related to water.  Moisture-related issues include freeze-thaw cycling, dehydration, condensation, and swelling.  Conservation scientist Mary-Lou Florian has written extensively about these issues, but moisture remains a persistent concern for many museum professionals.  A well established understanding of damage from fluctuations in relative humidity (RH) leads to the extrapolation that artifacts may suffer from swelling and condensation in cold environments since RH increases as temperature decreases.  Standard operating procedure for pest management at low temperatures involves sealing the object in a close-fitting polyethylene bag with a buffering material such as tissue paper.  The total amount of moisture inside the bag is finite and in fact very low (Florian 1990ab, 1992.)  Buffering materials compete with the object for humidity the air can no longer hold, and porous organic objects have the ability to accommodate small increases in RH.  The bag itself prevents condensation on the object after removal from the freezer.

 

Experience in the kitchen also influences the understanding of organic materials at low temperature.  Water is critical to issues of food preservation.  Ice formation causes the 9% expansion in water volume responsible for freeze-thaw damage.  (Franks 1985.)  An increase in membrane permeability at low temperature causes loss of turgor pressure and wilting of fresh plant materials (Reid 1987.)  Removal of water from a solution via ice formation causes the remaining solutes to increase in concentration.  These so-called “concentration effects” can drastically alter pH, viscosity, oxidation-reduction potential, salt concentration, and enzymatic reactions (Taylor 1987.)

 

The fact of the matter is, most museum objects do not possess sufficient moisture content to form ice.  Most organic artifact materials in a museum environment have between 8% and 12% moisture content (Florian 1986.)  Artifact material with an equilibrium moisture content (EMC) of up to 28% does not form ice at the temperatures used for pest control (Zachariassen 1985.)  It is for this reason that some conservators avoid the term “freezing” and its implication of ice formation when discussing museum pest management.  It is also worth noting that many materials can take weeks or months to reach EMC at room temperature, and cold temperature tends to slow the process even further (Grattan and Barclay 1988, Howell 1996, Adelstein et al. 1997.)  The low temperature moisture content in the closed bag situation at approximately -20C is in fact rather unique and analogies are not easily found in the literature from other fields.  

 

Dr. Dana Elzey, research assistant professor of materials science at the University of Virginia, Charlottesville, VA consulted on the potential problems related to low temperature exclusive of moisture issues.  These areas of concern include shrinkage, embrittlement, thermal shock, polymorphic phase change, and molecular alteration.  Shrinkage may serve to counteract that small amount of swelling mentioned earlier.  Practically all materials shrink as temperature is lowered because of reduced vibration on the molecular level.  The coefficient of thermal expansion (CTE) is a measure of this change and is dependent on the strength of interatomic bonds.  Materials with weaker bonds, such as many organics, shrink more than those with stronger bonds, like metals.  At low temperatures, composite objects may be at risk for damage from “CTE mismatch.”  There are published tabulations for expansion coefficients on some common materials, but there may be no data for many materials in aged or altered condition, no data in the appropriate temperature range, or simply no data at all.  Often materials are simply categorized as high or low relative to each other.  During cooling, the low CTE material goes into tension and risks cracking or delaminating while the high CTE material is in compression and in danger of deformation or crushing.  CTE mismatch can also be seen within a single material, particularly one that demonstrates anisotropy.  The bonds in anisotropic materials are direction dependent and expand differently in different directions.  Examples include materials that tend to crack in a preferential direction, such as wood, bone, tooth and lamellar structures.  Cracking is not the only manifestation of CTE mismatch.  If the high CTE material is sandwiched between two layers of low CTE material, it may be extruded by pressure from the surrounding material.  While many materials have the ability to deform elastically and then recover, at sufficiently high stress some materials may lose the ability to deform elastically, resulting in non-reversible plastic deformation or failure.  

 

Embrittlement is another area of risk that may be reversible upon warming if elastic deformation is not exceeded.  Embrittlement occurs at low temperatures because molecules are resistant to motion.  The glass transition temperature (Tg) is an indicator of material flexibility.  Below Tg, applied stress may cause brittle fracture; above Tg, elastic deformation is more likely to occur.  Examples of materials that become brittle at temperatures used for pest control include rubber, oil paint, synthetic polymers, acrylic paint and soft vinyl (Michalski 1991.)  Vibration from a faulty freezer or rough handling before the object returns to room temperature are two sources of stress.  Embrittlement is usually reversible upon warming.

 

Any discussion of the risk of damage from shrinking should include an introduction to the terms “ratcheting” and “shakedown.”  Ratcheting describes the accumulation of plastic strain.  A ratcheting crack grows each time it is exposed to the same stress.  Damage evolution due to this kind of cycling is known as fatigue and will eventually lead to macroscopic failure.  The other option, shakedown, involves a reduction of the incremental strain per cycle.  Most of the damage in this process occurs the first time an object is opposed to stress, and each subsequent cycle results in less damage per cycle (Elzey 2001.)

 

Thermal shock is the condition in which rapid temperature change leads to excessive internal stress resulting in damage or failure.  It is the phenomenon that causes a hot ceramic plate to shatter under cold water.  Several factors influence magnitude of stress: overall change in temperature, rate of cooling, size of the object, coefficient of thermal expansion, elastic stiffness, conductivity, and strength.  Objects most at risk for thermal shock have high CTE, high elastic stiffness, low thermal conductivity, and low strength.  A large, rapid change in temperature increases the risk of thermal shock.  Although most organic materials possess high coefficients of thermal expansion, conduct heat poorly, and are held together by low-strength secondary bonds, they have the advantage of very low elastic stiffness and are comparatively resistant to the effects of thermal shock.  It is the inorganic components of certain composite objects that are of concern here.  

 

Polymorphic phase change is another factor to consider in low temperature pest management.  Phase change involves a change in state, such as from solid to liquid or liquid to gas.  Polymorphic phase change involves a solid-to-solid phase change from one crystalline arrangement to another.  In some cases, one polymorphic phase may be more stable than another at low temperature.  Tin disease is one such example.  At room temperature, pure tin is a shiny white metal.  As temperature decreases, a non-metallic crumbly gray powder becomes the more stable form, reaching a maximum stability at -30C.  Tin disease is inhibited by most of the common alloying metals used with tin.  Most of the museum’s tin artifacts, such as cone tinklers on Native American artifacts from the Great Plains, are alloys and therefore safe from polymorphic phase change in the freezer.  However, the textbook example of tin disease involves Napoleon’s attempted 1812 winter invasion of Moscow, which failed in part due to the disintegration of the pure tin buttons on the soldiers’ clothing.  Low temperature is also a factor in structural change because some materials, such as rubber and some fats and waxes, become crystalline at low temperature.  This phenomenon seems to be at least partially reversible upon warming (Baker, 1995.)

 

The final area of concern addressed here is molecular alteration, particularly regarding protein denaturation, lipid autoxidation, and loss of moisture regain in materials demonstrating hysteresis. Conformational stability in protein is dependent on a complex energy balance involving a variety of intermolecular forces.  Cooling weakens some forces, such as hydrophobic interactions, but enhances others, such as hydrogen bonding (Taylor 1987.)  The technology to study proteins at low temperature in the absence of ice formation has only been developed in the past decade.  The formation of ice and the concentration effects that occur when water is removed as ice forms continue to be at the center of scientific research, making the question of permanent denaturation of proteins from low temperature alone difficult to resolve (Taborsky 1979; Fahy 1995; Franks 1995.)

 

The Arrhenius equation states that the rate of chemical reactions tends to slow with decreasing temperature.  The oxidation of lipids is sometimes an exception.  Lipids contain a wide variety of fatty acids that differ in chemical and physical properties as well as their susceptibility to oxidation.  Some follow the Arrhenius equation and oxidize more slowly at room temperature.  However, low temperatures can accelerate autoxidation of unsaturated fatty acids (Karel 1985.) Mechanisms for this are frequently described in the literature as “enzyme-catalyzed.”  Since enzymes are proteins produced by living organisms functioning as biological catalysts in living organisms, it is doubtful that there are any active enzymes remaining in museum artifacts.  

 

“Because enzymes function nearly to perfection in living systems, there is great interest in how they might be harnessed to carry on desired reactions of practical value outside living systems.  The potential value in the use of enzymes (Separate from the organisms that synthesize them) is undeniable, but how to realize this potential is another matter.”    (Roberts and Caseiro 1977.)

 

Furthermore, solute concentration effects that allow enzymes and substrates to come into contact influence some enzymatically-catalyzed oxidation in lipids (Reid 1987.)  Museum objects that cannot form ice are not subject to concentration effects. 

 

The loss of moisture regain ability due to changes on the molecular level is another potential concern.  Many organic materials are able to absorb and desorb moisture to keep in equilibrium with environmental humidity.  Taking up moisture brings them to a more stable energy state and generally occurs faster than desorption, as the material is reluctant to give up that moisture.  This relationship between water activity and moisture content is illustrated by a sigmoidal curve known as the moisture sorption isotherm.  For example, room temperature wool at 55% RH has a lower moisture content if it is in the process of getting wetter than it does under the same conditions if it is getting drier.  At low temperatures, molecules with potential water-holding sites may draw closer together and bond, creating a reduced capacity to hold water in the future.  (Timar-Balazsy and Eastop 1998.)  The conservation literature suggests there may be a distinction between damage from long term cold storage and short term low temperature exposure for pest control (Wolf et al. 1972; Williams et al. 1995; Pool 1997.)  

 

CONCLUSIONS

Exploration of the literature and consideration of materials science issues raise two areas of concern.  One involves the likelihood of repeated freezing cycles for some objects, particularly those actively loaned or exhibited and therefore subjected to low temperature treatments with each re-entry into the museum collection or new venue.  Data involving wood (George et al 1992; Erhardt et al. 1996;) textiles (Holt et al. 1995; Jansson and Shishoo 1998; Peacock 1999), synthetic fishing gear (Toivonen 1992;) paper (Bjordal 1998) and insect collections (Rawlins 2001) suggest no significant structural damage with repeated low temperature treatment for pest control.  Theoretically, however, embrittlement, shrinkage, and thermal shock have the potential to cause damage if the limits of elastic deformation are exceeded, or if ratcheting occurs within the elastic range and leads to fatigue (Elzey 2001.)

 

The second area of concern involves the permanent physical changes that are likely to occur (and perhaps accumulate) on a molecular level but remain invisible to the naked eye, such as loss of strength, loss of elasticity, distortion, crystallization, molecular alteration, protein denaturation, and loss of regain ability.  In some cases there may be synergistic effects in which interrelated damage mechanisms combine to cause further problems.  

 

In summary, it might be helpful to state this information plainly.  Based on this investigation which involved freezing several hundred artifacts, reviewing the literature, and discussing the topic with many museum and scientific professionals, a list of factors has been prioritized from highest-to-lowest concern.  On the whole, low temperature pest control appears to be safer for artifacts than might have been suspected.  

 

1. Freeze-thaw and dehydration should not occur because there is not enough moisture in museum artifacts.  

2. Condensation should not happen if artifacts are bagged properly.  

3. Swelling probably happens a little bit, but not much because there is so little moisture inside the sealed bag.

4. Polymorphic phase change does happen with some materials, usually fats and waxes, but this is usually reversible upon warming except in rare cases such as tin disease.

5. Thermal shock is not an issue for most organics because the temperature change is not drastic or sudden enough.  Inorganics are at greater risk, but no reports of this kind of damage were found.

6. Shrinkage undoubtedly occurs, but at this temperature it’s fairly minor and perhaps counteracted by the small amount of swelling.  The reason it is placed higher on the list is because of CTE mismatch danger.  Drums are one of the few objects not frozen at the NMAI.  

7. Embrittlement is also very likely to happen, but is usually reversible upon warming and objects are mainly at risk from vibration or rough handling until they warm up.

8. Molecular alteration is a bit of a wild card.  Protein denaturation may occur, but it may be reversible upon warming.  As far as lipid autoxidation goes, this may not happen at all without enzymes and sufficient moisture content.  Loss of moisture regain ability appears to be more of a danger with long term cold storage.

 

ACKNOWLEDGEMENTS

Thanks to Dr. Dana Elzey, department of Materials Science and Engineering at the University of Virginia, and the staff at NMAI, including Marian Kaminitz, Emily Kaplan, Jessie Johnson, and Leslie Williamson for their support and feedback.  I would especially like to acknowledge Mary-Lou Florian for her excellent work on this topic.  Thank you to the Andrew W. Mellon Foundation for making this research possible.

 

REFERENCES

Adelstein, P.Z., J.L Bigourdan, and J,M, Reilly.  1007.  Moisture relationships of photographic film.  Journal of the American Institute for Conservation 36(3):193-206.

 

Baker, M.T. 1995. Ancient Mexican rubber artifacts and modern American spacesuits: studies in crystallization and oxidation.  In Materials issues in art and archaeology.  vol. 4, ed. P.B. Vandiver et al.  Pittsburgh: Materials Research Society. 223-232.

 

Baker, M.T. 1995. Thermal studies on ancient and modern rubber: environmental information contained in crystallized rubber.  In: Resins: ancient and modern.  ed. M.M. Wright and J.H. Townsend. Edinburgh: Scottish Society for Conservation and Restoration. 53-56.

 

Bjordal, L. 1998.  Effects of repeated freezing on paper strength.  Proceedings of the third Nordic symposium on insect pest control in museums.  Stockholm, Sweden: Naturhistoriska Rikmuseet. 54-56.

 

Elzey, D.M. 2001. The effects of thermal cycling on the structure and properties of solids.  Lectures given at the National Museum of the American Indian Research Branch, Bronx, NY and Cultural Resource Center, Suitland, MD.   Department of Materials Science and Engineering.  University of Virginia, Charlottesville, VA.

 

Erhardt, D. M.F. Mecklenburg, C.S. Tumosa, and T.M. Olstad.  1996.  New versus old wood: differences and similarities in physical, mechanical, and chemical properties.  In ICOM Committee for Conservation preprints.  ed. J. Bridgland.  11th Triennial Meeting, Edinburgh, Scotland. Paris: ICOM. 903-910.

 

Fahy, G.M. 1995 Cryobiology: the study of life and death at low temperatues.  21st century medicine.

 

Florian, M.L. 1986.  The freezing process: effects on insects and artifact materials.  Leather Conservation News 3(1): 1-4.

 

Florian, M.L. 1990a.  Freezing for museum pest eradication.  Collection Forum 6(1):1-7.

 

Florian, M.L. 1990b.  The effects of freezing and freeze drying on natural history specimens.  Collections Forum 6(2):45-52.

 

Florian, M.L. 1992. Saga of the saggy bag.  Leather Conservation News. 8:1-11.

 

Franks, F. 1985.  Biophysics and biochemistry at low temperatures.  Cambridge: Cambridge University Press.

 

Franks, F. 1995.  Protein destabilization at low temperatures.  In Protein Stability. ed. D.S. Eisenberg and F.M. Richards.  Advances in Protein Chemistry 48.  New York: Academic Press.  105-139.

 

George, M.F., B.C. Cutter and P.P.S. Chin. 1992. Freezing of water in hardboard: absence of changes in mechanical properties.  Wood and Fiber Science.  24(3):252-259.

 

Grattan, D.W., and R.L. Barclay.  1988.  A study of gap-fillers for wooden objects.  Studies in Conservation.  33(2):71-86.

 

Holt, L., Y. Chen and W. Dodd.  1995.  The effect on wool fabrics of multiple freeze/thaw treatments for insect control.  Textile Conservation Newsletter 29:28-35.

 

Howell, D. 1996.  Some mechanical effects of inappropriate humidity on textiles.  In ICOM Committee for Conservation Preprints, ed 1.  J. Bridgland. 11th Triennial Meeting.  Edinburgh, Scotland.  Paris: ICOM. II:692-698.

 

Jansson, P., and R. Shishoo. 1998.  Effect of repeated freezing treatment on the mechanical properties of new wool.  Proceedings of the third Nordic symposium on insect pest control in museums.  Stockholm, Sweden: Naturhistoriska  Rikesmuseet.  57-60.

 

Karel, M. 1985.  Lipid oxidation, secondary reactions, and water activity of foods.  Autoxidation in food and biological systems.  New York: Plenum Press.

 

Michalski, S. 1991.  Paintings: their response to temperature, relative humidity, shock, and vibration.  In: art in transit: studies in the transport of paintings.  ed. M.F. Mecklenburg.  Washington, DC: National Gallery of Art.  223-248.

 

Peacock, E.E. 1999.  A note on the effect of multiple freeze-thaw treatment on natural fiber fabrics.  Studies in Conservation  44(1): 12-18.

 

Pool, M.A., 1997.  Preliminary analysis of the effects of cold storage on fur garments and mammal skins.  Collection Forum  13(1):25-39.

 

Rawlins, J. 2001.  Personal communication.  Section of Invertebrate Zoology, Carnegie Museum of Natural History.  Pittsburgh, PA.

 

Reid, D.S. 1987.  The freezing of food tissues.  In The effects of low temperatures on biological systems.  ed. B.W.W. Grout and G.J. Morris.  London: Edward and Arnold Publishers. 478-487.

 

Roberts, J.D. and M.C. Caserio.  1977.  Basic principles of organic chemistry.  Reading, Massachusetts: W.A. Benjamin Inc. 1270.

 

Taborsky, G. 1979.  Protein alterations at low temperatures: an overview.  In Proteins at low temperatures.  Ed: O. Fennema.  Advances in chemistry series 180.  Washington DC: American Chemical Society: 1-26.

 

Taylor, M.J. 1987.  Physio-chemical principles in low temperature biology.  In The effects of low temperatures on  biological systems.  ed. B.W.W. Grout and G.J. Morris.  London: Edward Arnold Publishers. 17-23.

 

Timar-Balazsy, A. and D. Eastop.  1998.  Chemical principles of textile conservation.  London: Butterworth-Heinemann.  15-25.

 

Toivonen, A.L. 1992.  Investigation of the effects of cold winter conditions on fishing gear materials.  Journal of the Textile Institute 83(1):163-177.

 

Williams, S.L., S.R. Beyer, and S. Kahn.  1995.  Effect of “freezing” treatments on the hydrothermal stability of collagen.  Journal of the American Institute for Conservation.  34:107-112.

 

Wolf, M., J.E. Walker, and J.G. Kapsalis.  1972.  Water vapor sorption hysteresis in dehydrated food.  Journal of Agricultural Food Chemistry 20 (5):1073-1077.  

 

Zachariassen, K.E., 1985. Physiology of cold tolerance in insects.  Physiological Review 64(Oct):799-832.


Integrated Pest Management Made Easy

March 19, 2009

http://www.museums.state.ak.us/documents/bulletin_docs/bulletin_29.pdf

Bulletin No 29, Winter 2007

Your building has pests.  Yes, it really does.  Ours does, too.  But are they a threat to your collection?  With an Integrated Pest Management (IPM) system, you can be active in your prevention of infestation and effective in your response if one occurs.  In the past, museums would respond to evidence of an infestation with poisons.  Many of those substances are now illegal, some contaminated or damaged the artifacts, and most were dangerous to museum staff as well.  Museums took a cue from the agriculture industry, which needed to control bugs on stored grains without contaminating the food with toxins.  An IPM system uses good housekeeping to keep pests out, traps to monitor the presence of bugs, and low temperature to treat infestations.

1. Good housekeeping aims to keep the pests out in the first place.  If you can avoid carrying in new pests, prevent them from entering the building from outdoors, and reduce things that attract them, you’re preventing the problem in the first place.  Here are some of our policies at the Alaska State Museum:
*       Eating is only allowed in the kitchen and conference room.
*       Eating during receptions is kept in a limited area.  The carpet is vacuumed immediately afterwards and trash is disposed of outside the building right after the event.
*       Beverages are not permitted at staff desks with the exception of water, coffee or tea in a closed container.
*       Collections spaces are kept free of non-collections materials and clutter is not allowed.  The cleaner your space, the quicker you will notice something is not right.
*       Packing materials are disposed of in the dumpster outside the building.
*       No plants or flowers are allowed in the building.  None.  They are a proven source of bugs as well as food for the bugs.
*       Structural gaps in the building are closed with silicone caulk, weather stripping or door sweeps.  For rodents, brassy steel wool can plug holes (and doesn’t rust.)  Mice can get through spaces the size of a quarter.
*       ¼” steel hardware cloth is used to cover floor drains.  Rats swim!
*       Keeping water drains on the roof clear eliminates many gnats. Usually a hose works fine.

2. Monitoring your populations with sticky traps gives you an early warning of trouble afoot.  We order our traps through Insects Limited: (317) 896-9300 www.insectslimited.com  The cost is approximately $50 for a box of 100 traps that can be torn into thirds.  That makes 300 traps at about 17 cents each.  For our three floors and approximately 24,000 square feet, we set about 50 traps.  They are also called “blunder” traps, so place them where a bug is likely to stroll in.  This includes along the wall, near sources of water like drains, and next to doorways.  Number each location on a map, and label each trap with its number, location and date.  Change the traps every three months, and keep a chart that describes what you found in each trap.  This task usually takes about 3 hours at the ASM.  If you take a flashlight, checking those dark corners for rodent droppings or other debris is also useful.  Our traps at the Alaska State Museum usually contain lots of spiders and sowbugs (also called pillbugs) as well as ants, large black click beetles, and centipedes.  Google images is helpful, and so are www.bugguide.net and www.museumpests.net.  When we find an insect that looks like a “heritage eater,” but we aren’t sure, we put out extra traps in that location for next time and send the trap to the Forest Service for positive identification.  We also ask staff to catch any bugs they see on a piece of scotch tape.  Anything that was originally a plant or animal has potential for insect infestation.  At the top of the list for tasty bug treats are fur, feathers, leather, and wool.

3. Treatment involves a freezer.  Research indicates that our “heritage eaters” can be killed in all phases of their life cycle by one week below -20°C.  However, many museums only have access to a frost-free freezer, with temperatures that cycle well above -20°C.  Many insects are “frost tolerant” and can make a substance like antifreeze to survive a dose of cold.  But our brains are bigger!  The artifact can be placed in the freezer for a week, then removed and allowed to reach room temperature for 24 hours, and put back in the freezer for another week to deliver a deadly second round of cold.  It is very important to package the artifact properly for low temperature treatment.  You must wrap the artifact in a soft absorbent material such as plain tissue paper, white paper towels, or a soft cloth.  This helps protect it against both the increase in relative humidity at lowered temperature and the slight increase in brittleness when things are cold.  Then, the artifact needs to be placed in a plastic bag that is well sealed.  Squeeze as much air from the bag as you can and seal the Ziplock or use a heat sealer if possible.  Lucky for us, most museum artifacts don’t have enough water in them to create ice.  However, upon removal from the freezer, condensation will form, and it is much better for that moisture to form on the plastic bag than on your artifact!  After a day of adjusting to room temperature, you can safely remove your artifact from the package.  Removing all the old bug debris is a good idea, so any future bug debris will be a clue to a new infestation.  Brushing the debris into the nozzle of a vacuum cleaner with a soft paintbrush usually does the trick.

When infestations occur, not only do the artifacts go into the freezer, but the infested space must be vacuumed, carpet steam-cleaned, and the perimeter of the area dusted with boric acid.  Occasionally, it is necessary to turn to bait.  Ant traps and D-Con are examples of bait, which are not pesticides but kill the pest through mechanisms like thinning the blood to induce internal bleeding.  Bait typically kills much more efficiently than traps.  A recent infestation of picnic ants at the Alaska State Museum was controlled with ant bait that was carried back to the nest.

Many museums do preventive treatment of incoming artifacts with the freezer.  A donation of a fur parka, for example, would definitely go in our freezer before it went into our clean collections room.  What if you don’t have a freezer, or the incoming artifact is too big?  Careful visual inspection in dark crevices can help set your mind at ease.  Look for holes, loose hair, bald patches, live bugs, bug parts, cocoons, webbing, bug nests, and tiny bug droppings known as “frass.”  Frass is round, so suspicious looking dirt can be sprinkled on a piece of paper and the paper tilted…if it rolls easily, it might be frass.  If you don’t see this evidence, the next step is to lay the artifact on a pristine white surface and place some sticky traps around it.  Wait two months or so to allow any eggs to hatch and get active.  If you see no debris on the white surface and nobody in the sticky traps, you’re probably safe.  Preventive treatment is also done with items for sale in the Alaska State Museum gift shop.

An Integrated Pest Management system is part of professional museum practice, just like monitoring your temperature and relative humidity, and keeping your light levels appropriate.  Dealing with an infestation after it happens is upsetting, time consuming, difficult, and often means irreversible damage to museum collections.  An ounce of prevention is truly worth a pound of cure.  Have questions?  Call us!  Scott Carrlee 465-4806 or Ellen Carrlee 465-2396.

Heritage-eating bugs

Common Heritage Eaters
1:00 Cigarette beetle
2:00 Drugstore beetle
3:00 Confused flour beetle
4:00 Saw-toothed grain beetle
5:00 Carpet beetle (black, white, and orange)
6:00 Common carpet beetle larvae
7:00 Varied carpet beetle  (black, white and gray)
8:00 Common dermestid beetle
9:00 Larder beetle
10:00 Webbing clothes moth (ragged wings)
11:00American spider beetle
12:00 Hide beetle (has white tummy)

insect debris

Insect debris from L to R: light brown frass and wood bits from a powder post beetle infestation, #2 pencil, larva and striped shed larval casings, soft white cocoons from the casemaking clothes moth.
Harmless bugs

 
A dime gives scale to these “harmless” bugs as well as the generally smaller-sized “heritage eaters.”

1:00 and 2:00 spiders are very common and may make webs and nests but eat other insects, not collections.  A spider population out of control can be reduced by setting out a large number of sticky traps.
3:00 Minute scavenger beetles eat mostly molds and fungi.  These were living in damp plastic bags used to stuff out a mukluk.
4:00 Common weevil, a grain eater.
5:00 Carpenter ants do not eat artifacts, but if you see one, your building itself could be in trouble.
6:00 Common housefly, mostly a nuisance for leaving droppings called “flyspecks” on artifacts.
7:00 Picnic ants are looking for sugar.  This one was attracted to a puddle of punch spilled under a printer during a reception.
8:00 and 9:00 Sowbugs or pillbugs come in many shapes and are found in damp areas.
10:00, 11:00 and 12:00 Carabids, click beetles and other large beetles are generally harmless and die soon after coming indoors


Dust in Museum Exhibits

March 19, 2009

Bulletin 30, winter 2008  No pdf link on website yet.

We have long known that dust causes damage to artifacts. The basic
information we tell museums about dust includes:

1.      Dust is unsightly and makes your collection look poorly
maintained.
2.      Dust is abrasive on a microscopic scale due to tiny sharp
mineral particles, such as quartz.
3.      Dust contains pollens, skin cells, insect bits, and other
organic matter that feeds biological growth.
4.       Dust can be acidic.
5.       Dust is “hygroscopic,” meaning it attracts water and holds it
against the surface of an object, contributing to staining, corrosion,
and biological growth.

Recent articles have given us a new understanding of the impact of dust
on our collections.  A paper presented at the 2004 conference of the
American Institute for Conservation  described the forces that help dust
stick to surfaces.  One of these forces comes from sticky “exopolymers”
made as a waste product of microbes (mainly bacteria).  Accumulating
dust provides more food for these colonies of microbes, and layer upon
layer of “biofilm” forms, with the bottom layers becoming firmly adhered
to the surface of your artifact.  Spikes in humidity can encourage the
initial growth and speed the growth of biofilms.  Periods of low
humidity after high ones can stress the bacteria, and might cause them
to produce even more sticky exopolymers.  Yet another reason to try to
keep our museum humidity levels stable!

Other recent articles have explored the role of visitors in creating
coarse dust.  Considerable amounts of dust enter the museum on visitors’
clothes and shoes. Visitors are such a direct contributor to dust that
one study showed dust amounts are cut in half for every 3 to 4 feet of
distance between a visitor and an object. Fibrous dust, largely from
clothing, accounts for only about 3% of the dust in exhibits. But since
the particle size is large and visible, fibrous dust contributes
significantly to the appearance of dustiness. This dust tends to be
thickest at eye level. Dust entering on shoes is more concentrated
closer to the entry, and in greater quantity under wet weather
conditions than dry conditions. This kind of dust only rises about 4 or
5 inches off the floor.

Some preventive measures can be taken. Placing objects in cases and
further away from visitor traffic is one solution, of course, but is not
always possible or desirable. Tightly sealed exhibit cases are better
than ones with gaps, but require construction materials that do not
off-gas harmful chemicals like formaldehyde and acid.  Placement of mats
in entryways significantly reduces the amount of dirt brought into the
building on shoes. Vigorous air movement also increases the rate of dust
coverage. Live performances and pathways through exhibits that involve
sharp turns are examples of “dust raising” activities. Air movement from
fans and open windows encourages dust circulation as well. Sometimes
those factors are unavoidable, but strategic decisions can be made,
particularly in relation to artifacts on open display.

Cleaning of collections on exhibit should be scheduled at least once a
year. Objects displayed in the open should be dusted annually. Artifacts
in exhibit cases can be cleaned on a rotating schedule, with a few
exhibit cases cleaned one year and others the next. After a few years,
all cases will be done and the rotation can begin again. It is useful to
have a map of exhibit galleries that can be annotated with notes and
condition reports if needed.

Good housekeeping is divided into two levels of cleaning. Regular
less-skilled cleaning can be done by janitorial staff or untrained
volunteers, including daily vacuuming and regular dusting of furniture.
Specialized cleaning of exhibits requires more skill. HEPA-filtered
vacuums are especially helpful, since they release less dust back into
the air than traditional vacuum cleaners. Closer to collections objects,
vacuums with adjustable suction (such as a Nilfisk vacuum with a
rheostat) are preferable. Dusting techniques that involve rubbing are
abrasive to most surfaces on a microscopic level, and are best avoided
if possible. Most items can be effectively cleaned with a soft
paintbrush, gently fluffing the dust from the surface into the nozzle of
a vacuum cleaner. For fragile surfaces, you may cover the nozzle with
fine nylon netting, such as tulle, secured with a rubber band.  Many a
loose bead or detached fragment has been saved this way, and you will
see sooner if the suction is too strong (hairs pulled from a taxidermy
specimen, for example).  Feather dusters can be helpful, but beware of
any rough quills that could scratch surfaces and be sure to vacuum the
feathers frequently to remove dust.

Glass and plexiglass surfaces are often the first to show dust. The
Sheldon Jackson Museum in Sitka, which has some of the cleanest exhibit
galleries in the state, has found that cleaning glass with paper towels
and a mixture of 1 part white vinegar to 4 parts water is as effective
as any cleaner. Any cleaner should first by applied to a cloth, and then
to the glass or plexi. Fine mist spray can penetrate cracks of exhibit
cases and damage artifacts. Always be careful to let the case air out
before closing because of the acetic acid or ammonia vapors released by
some cleaners.

Plexiglas(r) requires special attention to prevent the plastic from
fogging or scratching. The Alaska State Museum uses specially formulated
commercial Plexiglas(r) cleaners. One product is called Norvus, and is
available on the Internet through vendors such as Amazon.com and Tap
Plastics.  Novus 1 is for cleaning, Novus 2 is for removing fine
scratches, and Novus 3 removes heavy scratches. Apply with a clean
cotton rag.

Good housekeeping is an important part of preventive conservation.
Cleaning also gives you an opportunity to inspect your exhibits for
problems such as bugs or shifted objects. While updating exhibits is
often not in the budget, dusting costs little and freshens up
appearances.

(sidebar)

Five Defenses Against Dusty Exhibits
1. Sealed exhibit cases are the gold standard.
2. Establish regular dusting schedules.
3. Use extra floor mats near doors.
4. Avoid the use of fans and open doors or windows unless absolutely
necessary.
5. Avoid drastic swings in humidity levels.
6.  Shut down the HVAC when cleaning dust out of the vents.

References:

Tarnowski, Amber L., Christopher J. McNamara, Kristen A. Bearce, and
Ralph Mitchell.  “Sticky Microbes and Dust on Objects in Historic
Houses.”  AIC Objects Specialty Group Postprints, Vol. 11, 2004.
 Yoon, Young Hun and Peter Brimblecomb.  “Dust at Febrigg Hall.” The
National Trust View, Issue 32, Summer 2000.


New Frontiers for the Conservation Lab

March 19, 2009

http://www.museums.state.ak.us/documents/bulletin_docs/bulletin_26.pdf

Bulletin 26 Spring 2007

Published as “Conservator’s Corner”

by Ellen Carrlee

 

Along with other renovations in the Alaska State Museum basement, the
conservation lab has had a makeover, with new flooring, new paint, and
new lab tables.  The spruced-up space will be used for treatments, the
conservation library, the conservator’s office area, textile
conservation supplies, study samples (fragments of ivory, skin, basketry
and other materials for developing treatments) and the binocular
microscope.  The new tables for treatments have chemical-resistant black
resin tops and are the kind typically used in college chemistry
classrooms.  The narrow former darkroom that served as the only
conservation lab space for many years can now be used more effectively
as the conservation chemical laboratory, with its deep sinks, fume hood,
and safety features such as a flammables storage cabinet and emergency
eyewash station.  Most conservation treatment supplies are stored there,
and certain wet treatments will still occur in that space.  First on the
docket will be a basketry conservation project to finish the treatment
of several waterlogged archaeological baskets from southeast Alaska.
Among the most important are two very old baskets that have already
received impregnation with polyethylene glycol (PEG) wax to replace the
excess water.  Water has such strong surface tension that simple
evaporation from old waterlogged wood and basketry materials causes
warping and severe damage.  While the PEG treatment was successful in
halting deterioration, these ancient baskets are still too fragile to be
exhibited.  A consolidation is needed, and research is underway to
determine the best approach.  Two graduate students in conservation will
be coming to assist in this project as well as treat other baskets in
the ASM and SJM collections.  Molly Gleeson will be coming from the
UCLA/Getty Museum art conservation program, and Samantha Springer will
be coming from the Winterthur/University of Delaware art conservation
program.  They will arrive in mid-June, spending several weeks in Juneau
working on the collection and learning about gathering and processing
spruce root and an introduction to weaving from Tlingit/Haida weaver
Janice Criswell.  Then they will travel to Sitka to work on the Sheldon
Jackson Museum collection and learn more about weaving from Tlingit
weaver Teri Rofkar until mid-August.  The interns will also share their
knowledge and treatment techniques with the weavers in what promises to
be an exciting and rewarding collaboration.  Successful treatments will
mean many important historical and archaeological baskets currently too
fragile to be exhibited will be able to be studied, appreciated, and
enjoyed by the public.

 

Conservation Lab BEFORE

Conservation Lab BEFORE

 

Conservation Lab AFTER

Conservation Lab AFTER


2007 Basketry Internship

March 19, 2009

http://www.museums.state.ak.us/documents/bulletin_docs/bulletin_27.pdf

Bulletin Vol 27 Fall 2007

The Alaska State Museum conservation lab hosted two interns for a basketry conservation project this summer.  Both interns were graduate conservation students finishing their second year of studies: Molly Gleeson from the UCLA/Getty Museum program, and Samantha (Sam) Springer from the University of Delaware/Winterthur Museum program.  These programs and the interns themselves provided the funding to come to Alaska.  The ASM provided the supplies and supervision.  In the first week, Molly and Sam brainstormed treatment solutions for the archaeological basketry fragments in the lab, and did a preliminary cleaning on a group of flattened spruce root work baskets that may become a study collection.  In the second week, curator Steve Henrikson assigned each intern two horrifically damaged baskets.  Molly worked on two Haida baskets collected by Lt. George Thornton Emmons in the late 1800’s.  The baskets had severe deformation, losses, tears, and old repairs of painted tape.  Sam’s Tlingit basketry projects also had intense tears, losses and deformation as well as old insect infestation and surface soiling.  The two Tlingit baskets still retain the inverted Y-shaped folds on the sides that indicate the baskets were folded for storage and thus not made for the tourist market.  Treatments included overall re-shaping in a humidity chamber, localized humidification with Gore-tex and blotter paper to align tears for repair with tiny splints of Japanese tissue and wheat starch paste, and innovative loss compensation with cotton gauze and sculpted paper pulp bulked with adhesive.  The interns were also able to examine baskets in the collection with Steve Henrikson and Tlingit-Haida weaver Janice Criswell.  Janice and weaver Mary Lou King twice took the interns “rooting.” They dug spruce roots, processed them, and each wove a basket under the tutelage of Janice and Mary Lou.  Together the interns formed quite a dynamic duo, becoming fast friends and helping Ellen make improvements to the lab.  Molly’s boyfriend Germán visited from Chile and proposed marriage on a beautiful Eaglecrest hike.  Germán and Samantha’s husband Seth also became friends, hiking and seeking satellite TV soccer matches while their partners immersed themselves in basketry.  Samantha’s professor Bruno Pouliot from Delaware also visited the interns for several days, and accompanied them to Sitka to kick off the second part of their internship.  Their first day on the job, they appeared on the radio to promote that evening’s free public program at the Sheldon Jackson Museum, a Conservation Clinic to provide advice to locals about their artifacts.  The clinic included ASM Curator of Museum Services Scott Carrlee (also a conservator.)  More than fifty people came, most bringing artifacts for examination, making the event one of the most successful public programs at the SJM in recent years.  In addition to several basketry treatments, the interns were able to meet with retired curator Peter Corey, National Parks Service curator Sue Thorsen, and Tlingit weaver Teri Rofkar to study baskets.  They also gathered materials and wove baskets with Teri.  In an exciting development, the interns are working with Teri and Janice to co-author a paper for an important international museum conference.  The International Council for Museums Conservation Committee (ICOM-CC) holds a major conference every three years.  In 2008, the conference will take place in New Delhi, India with the theme “Diversity in Heritage Conservation: Tradition, Innovation and Participation.”  The basketry abstract was provisionally accepted in July.  Only 40% of the proposed abstracts were accepted, and final paper is due in November for final review.  If accepted, this will be one of the very few professional conservation papers that will include a first-person Native voice, instead of the Native perspective only interpreted through a conservator.  Internships such as this one provide up-and-coming conservation professionals an opportunity to work with Native artists and museum professionals in the environment where the artifacts were made, allowing for multiple perspectives and a deeper understanding of the conservator’s sensitive role in preservation.  These are lessons that can be carried on throughout their careers.  In return, interns take on difficult treatments and share the latest techniques and theories in conservation they have learned in school.  Today’s interns are tomorrow’s professionals, linking us to museums in the lower 48 and creating a network of colleagues.  The long-range plan for the ASM conservation program includes dividing the collection into materials groupings for systematic surveys.  Each survey will identify priorities for conservation treatment and provide ideal internships for future conservation students.  Next summer’s project targets the museum’s natural history collection.  Stay tuned…

Rim of spruce root basket 2006-18-1 BT by Samantha Springer

Rim of spruce root basket 2006-18-1 BT by Samantha Springer

 

 After treatment by Samantha Springer using Japanese tissue and paper pulp with wheat starch paste and watercolor.

After treatment by Samantha Springer using Japanese tissue and paper pulp with wheat starch paste and watercolor.

 

 

 

 

 

 

Molly Gleeson inventing a new repair technique using cotton gauze, paper pulp, Japanese tissue, wheat starch paste and PVA emulsion adhesive.

Molly Gleeson inventing a new repair technique using cotton gauze, paper pulp, Japanese tissue, wheat starch paste and PVA emulsion adhesive.

After treatment of large loss near base of Haida basket II-B-493

After treatment of large loss near base of Haida basket II-B-493

 

Janice Criswell teaches Samantha Springer to weave spruce root in Mary Lou King's kitchen.

Janice Criswell teaches Samantha Springer to weave spruce root in Mary Lou King's kitchen.


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