C O N S E R V A T I O N C E N T E R for Art and Historic Artifacts

S a l v a g i n g A r t o n P a p e r

Disaster Recovery

ll collections of works of art

on paper are vulnerable

to damage or destruction

as a result of natural disasters like

hurricanes, tornadoes, floods, or the

ravages of fire, burst pipes, or furnace

malfunction.Although disaster prepa-

ration and prevention can limit the

damage that occurs, serious injury to

a few or many artworks can neverthe-

less result from extreme weather,

smoke, fire, or mechanical failure.

This technical bulletin describes how

to plan an efficient recovery from dis-

asters affecting works of art on paper.

The discussion includes preparing

for a disaster; assessing damage and

setting salvage priorities; advantages

and disadvantages of various recovery

options; and additional resources for

information and advice.The emphasis

is on procedures for dealing with

water damage, with a brief section on

fire-related damage. In all emergencies

affecting art on paper, it is essential

that a paper conservator who is

experienced in disaster recovery be

included in the salvage process.

A

Water damaged etching. Christ and the Samaritan by Rembrandt. Courtesy of Bucks County

Historical Society.

FLOODS, HURRICANES,TORNADOES, STORMS,AND LEAKING PIPES

WATER DAMAGE

Works of art on paper can present uniqueproblems when wet. For each artwork,three separate elements may need to beconsidered: the paper support, the appliedmedia, and in some cases, a surface coatingor varnish. Each of these elements respondsdifferently to moisture. In addition, expo-sure of any of the elements to moisturemay encourage mold growth, resulting inserious damage to the artwork.

Paper, the first of these elements,expands from direct contact with moistureor even from elevated relative humiditywithin the environment.This can be particularly problematic if the paper isadhered within a mat or attached to anytype of mount or secondary support. Forexample, hinges along the top edge of thepaper will restrict that area, while the restof the paper may expand significantly.Thiscan cause distortion and possible tearing of the artwork.When the paper supportbecomes distorted, thickly applied mediasuch as gouache or India ink lose theirfirm attachment and may cleave away fromthe paper. Factors other than expansionmust also be considered when paper getswet. For instance, some colored papers,such as construction papers, are manufac-tured with a dye component that maybleed when wet.Artworks may also beexecuted on thick paperboard, which,when wet, may take a long time to dry;and unless the paperboard is dried in a stable environment with a moderate rela-tive humidity, mold growth may occur.

Applied media, the second element to be considered, can present varied andcomplex problems, particularly if a numberof materials are used on a single art object.Paints or drawing inks (especially watercoloror felt-tipped markers) may bleed or transfer onto adjacent materials.Thicklyapplied paints, such as gouache, acrylics,or oil paint, will expand at a different ratethan the paper support.This can result incracking and loss of the paint. Particulatemedia, which include pastels, charcoal,chalks, crayon, and pencil, are often susceptible to water damage; particles ofmedia may simply float off the substrate

and redeposit elsewhere on the paper sup-port. Oil-based inks, such as those used onengravings, may react with any salts presentin the water and weaken the inks. Silk-screened prints, mezzotints, and aquatints havea unique matte surface that is vulnerable toalteration by contact with water, causingdarkening or a change in the surface finish.

The third element to be considered is surface coatings, such as varnishes, whichmay blanch following contact with water,partially obscuring the design beneath. Gumglazes on top of watercolors are typicallyextremely water-soluble and usually cannotbe saved in the event of a water-based disaster.

For each of these elements, mold is the most serious potential source ofdamage to an artwork. It can weaken anddestroy the paper support of an artwork, aswell as cause intractable staining of paper,media, and surface coatings. Mold cangrow and spread rapidly within 48 hours of the initial exposure to water. Even if the artworks do not appear to be wet, adamp environment can cause mold growth.Mold may grow on works if the relativehumidity is higher than 65% and the temperature higher than 70ºF.

ASSESSING DAMAGE AND SETTINGSALVAGE PRIORITIES

In both small and large-scale disasters, aconservator's help is critical in assessing the damage. He or she can recommend thetypes of recovery procedures (described inthe sections following) best suited for thematerials affected. Procedures for handlingwet artworks will also need to be discussed,as well as a plan for transporting the itemsfor recovery.

The conservator will also be able tohelp set salvage priorities. Priority rankingsare typically based on the type and degreeof damage, the type of material affected,and the importance of the materials to the overall collection. In general, highlyvulnerable artworks should be quickly stabilized first.These works can include any that contain water-soluble media andcolored papers, as well as complex artworks(such as collages whose adhesive may failquickly when wet or works with mixedmedia) and those with thickly appliedmedia. Broader categories of artworks thatmay be especially at risk include oversizedworks (whose vulnerability to damage isincreased as a result of handling when wet),

D I S A S T E R R E C O V E RY T E C H N I Q U E S Guidelines for Disaster Response

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PREPARING FOR A DISASTER

A thoughtful and well-organized disasterpreparedness plan is essential for any insti-tution containing valuable paper-basedcollections. Disaster planning requires considerable staff time and administrativesupport. Potential hazards must be ana-lyzed, with consideration of factors specificto both the site and the building. Copiesof the collection inventory and accessionrecords should be maintained off-site.Priorities for salvage should be establishedbased on the significance of the artworks to the collection and their vulnerability.It is important for a conservator to be partof this planning process. If the institutiondoes not have a conservator on staff, ordoes not have a contractual arrangementwith one, creating an alliance with a conservator should be part of the disasterpreparedness plan.

Carefully chosen enclosure systemsplay a key role in making artworks less vulnerable to damage and in facilitating salvage efforts. Collections of art on papershould be housed properly in well-labeledindividual enclosures and boxes or in flatfiles.Valuable artworks executed in mediathat are unlikely to survive extreme contactwith water—such as pastels and watercol-ors—as well as a collection's treasures inany media should be stored in watertighthousing whenever possible.Artworks thatare kept in frames should be in sealedpackages that are dust- and water-resistant.(In this type of housing, the various com-ponents—glazing, matted artwork, backingmaterial—are sealed at the edges with tapeor laminate material.) At all times, artworksshould be stored at least a foot above thefloor to help guard against water damage.

Christ and the Samaritan after conservation

treatment.

IMMEDIATE CONSERVATIONTREATMENT

Contacting a conservator to immediatelytreat affected artworks is always the preferred option for safe and effective disaster recovery.This recovery option isstrongly recommended for any artworkthat exhibits mold growth.

AIR-DRYING

Air-drying is a procedure best used for drying small numbers of materials.Although larger quantities may be dried in this manner, staff will be needed to carefully monitor the process for any problems that may occur.

Whether or not to air-dry maydepend on the extent of damage, the typesof paper supports, and the media involvedin the affected works. Solubility of mediaor dyes in the paper support is the greatestpotential hazard of air-drying. Many typesof media may not show signs of solubilityuntil the drying phase—media that remainliquid can, through capillary action, bleedinto adjacent dry areas of the paper sup-port, causing feathering or sinking of themedia. If paint is mixed from two or morecolors, an additional danger is that one of the colors may sink during air-drying,yielding an apparent color shift in theimage. (For further information on making the decision to air-dry, see the box on “Air Drying” on page 4.) Generally,intaglio prints and lithographs respond wellto air-drying.

Air-Drying Procedures

Important Note: Remember that severe damagecan occur to an artwork by mishandling it whileit is wet. If you are unsure about handling anobject, consult a conservator first.Artworks damaged by mud or other contaminants mayneed to be rinsed by a conservator prior to air-drying.

1. Keep the works wet until they have beenseparated from storage enclosures and fromeach other.The separation should be doneby a conservator after the works have beentransported to a stable drying environment.To maintain wetness, cover the materialswith plastic sheeting or pack them in plas-tic garbage bags. Each package must besupported by a rigid board for transport.To prevent mold growth, be sure to initiate the drying procedure within 48 hours.

contemporary works, and naive and outsider art.

Priority is also usually given to very wet materials, partly because of theincreased risk of mold growth. If mold hasstarted to grow on any collection materials,isolate these artworks and contact a paperconservator. (For mold recovery proce-dures, refer to CCAHA's bulletin onManaging a Mold Invasion: Guidelines forDisaster Response).

OPTIONS FOR

RECOVERING WORKS

OF ART ON PAPER

Several recovery procedures may be considered for water-damaged artworks,including:

Immediate conservation treatment.

Air-drying.

Freezing.

In large-scale disasters, a combination ofthese techniques may be needed for a successful recovery.

Water damaged lithograph exhibiting foxing

stains from high humidity levels.

Portrait of Suzanne Amiée Cassirer 1909 by

Max Lieberman. Courtesy of private client.

3

•••

Advantages

Produces the most desirable outcomeof all recovery methods.

Good for significant or especially vulnerable artworks, including workswith water-soluble media such aswatercolors, drawing inks (especiallyfelt-tipped markers), and gouache.

If mold growth has started, immediatetreatment will prevent spreading ofmold and possible destruction of collection materials. Immediate treat-ment to reduce mold staining will alsoachieve the best results.

Disadvantages

Limitations include availability of conservation professionals; extent ofimmediate financial resources; and thenumber of damaged works.

Immediate treatment by a conservatorhas the greatest "up-front" cost per artwork of all recovery options.However, this cost may be offset by theneed to later treat the damaged works.

IMMEDIATE CONSERVATIONTREATMENT

2. Gather supplies for transport and drying. Rigid supports such as cardstock,blotter, or corrugated cardboard are useful for transporting wet artworks,particularly if the works are oversized.Drying supports include blotter, papertowels, or unprinted newsprint. Blotter is the most useful drying support becauseit can absorb the greatest amount ofmoisture per square foot and also retainssome strength when damp. Polyesterwebbing can be used to interleave works;however, do not stack artwork unless it isabsolutely necessary—sensitive media canbe damaged easily by placing anythingagainst their surfaces.

3. Secure a protected location with a stable environment to dry the artworks.Ideally, tables should be set up, but a cleanfloor is acceptable. Place drying supportson the drying surfaces prior to transport-ing the works. Set up fans to increase aircirculation. Fans should be directed awayfrom the drying surfaces.

4. Pack the works to be air-dried, andtransport them to the drying location.Ideally, very wet works should be handledby a conservator.Works should also behandled one at a time, faceup, with nothing touching the media, and as stated, should be transported on a dry,rigid support of cardstock, blotter, or corrugated cardboard. If large numbers of artworks with minimal damage are tobe air-dried, they can be systematicallypacked in numbered and reinforced cardboard boxes or plastic crates withpolyester webbing between each object.

Fire damaged etching. By William Hogarth.

Courtesy of private client.

FREEZING

If the quantity of affected works is large,freezing may be a desirable recoveryoption. Freezing is especially recommend-ed if the wet materials cannot be attendedto within 48 hours, to avoid the risk ofmold growth.

During the disaster-planning phase,institution staff should contact commercialfreezing suppliers to inquire about poten-tial services.Terminology on freezing can be confusing owing to the primaryapplication of freezing within the foodindustry. Be sure to know exactly whatservices you need and are contracting for.Vendors should also be aware that artworksshould not be dried to 0% moisture content. The normal moisture content of ahealthy paper support is 6–7% at 50% relativehumidity.

Freezing should never be used for artworks with thickly applied media orvarnishlike surface coatings. Freezing maycause cracking and loss of these elements.

Freezing Options

Freezing methods can be divided intothree categories:

Temporary freezing—freezing as a temporarymeasure to stabilize artworks while decid-ing how ultimately to dry them.

Freezer drying—freezing to dry the works, in either a commercial freezer or a standard home freezer.

Vacuum freeze-drying—freezing to dry the works while they are in a vacuumchamber to reduce distortion.

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Advantages

Good for works with thickly appliedmedia (gouache, acrylics, oil paint),but it is important to watch for watersolubility. Conservation examination of thickly applied media is recom-mended after air-drying to verify thatthe media remain firmly attached tothe paper support.

Appropriate for artworks with varnish or other surface coatings.

Very good for many stable prints (this can include etchings, engravings)on sturdy papers.

Often the least expensive of all recov-ery methods in terms of immediatecost. Hidden costs include treatmentthat may be needed later to rectifyproblems that occurred during air-drying, such as distortion, bleeding ofmedia, and formation of tidelines (linesof residue created by movement ofwater-soluble media, acids, or othercontaminants in the paper).

Disadvantages

Limited by availability of trained professionals, staff, and volunteers.

Process is labor-intensive.

Limited by available air-drying space.A secure, clean, dry, and cool space isneeded to safely dry the works.Thesize of the space needed will be determined by the number and size of damaged artworks.

Water-soluble media may be at riskduring drying—careful attentionshould be paid to watercolors,gouache, and drawing inks (especiallyfelt-tipped markers). Lateral bleedingmay later necessitate conservationtreatment.

Paper supports will distort. Fragilepapers that have distorted will need to be housed individually in boxes toavoid creases. Paper distortion can alsodisturb thickly applied media, causingit to crack and cleave away from thepaper surface.

Formation of tidelines can occur.

AIR-DRYING

After Treatment.

Temporary freezing of works onpaper allows for time to safely plan and organize the many steps needed to dry the affected materials, as well asto prepare a rehabilitation site.This canbe especially important if the collectionscannot be treated or dried quicklyenough to avoid mold growth. Materialsto be frozen should be interleaved orwrapped in wax paper, and carefullypacked in sturdy boxes. Large collectionsshould be transported in refrigeratedtrucks to a freezer facility. Small quantities may be placed in standardself-defrosting kitchen freezers or commercial freezer units.

Freezer drying the works completelycan be a safe and controllable way todry wet artworks. During this process,wet materials are quickly brought tolow temperatures.This is sometimesreferred to as "blast freezing" and isdesirable because it prevents the forma-tion of large ice crystals within thepaper structure.As the works dry, thepotentially damaging liquid state isbypassed, and the frozen water subli-mates directly to vapor.The vapor isremoved from the freezer unit duringthe defrosting cycle.This process is veryslow and can take up to six months.However, the process can be interruptedat any time to assess the materials.

Vacuum freeze-drying is similar tofreezer drying in many respects, but provides a faster drying time and less planar deformation to the paper support.In this process, a vacuum is created whilea controlled heat source is added to thesystem to promote sublimation of thefrozen water into gas. Despite the heatsource, the materials are kept frozen during the entire process, until dry.Thematerials will dry in approximately 48hours to two weeks.

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Advantages

Allows for time to make informeddecisions regarding recovery.

Avoids mold growth, which canoccur within 48 hours of the disaster.

Allows the collection to be recov-ered in batches, reducing the over-whelming magnitude of artworksneeding immediate attention.

Disadvantages

Is only appropriate for artworkswith thinly applied media and nosurface coatings.

TEMPORARY FREEZING

Advantages

Very good reported drying results—possibly the safest way to dry an art-work, short of immediate treatment bya conservator.

Good for works with thin-layer,water-soluble media such as watercolors.

Suitable for collages (i.e., adhesivesrespond well).

Disadvantages

Use is limited to artworks with thinlyapplied media and no surface coatings.

Some distortion of the paper supportwill result, but it will not be as severeas that caused by air-drying.

Due to lengthy freezer time, consid-ered to be the second-most-costly ofall recovery options (in terms of up-front costs).

FREEZER DRYING

Advantages

As in freezing, this process is onlyacceptable for works with thin-layer,water-soluble media such as watercolors.

Suitable for collages (i.e., adhesivesrespond well).

The vacuum reduces warping ofmaterials.

Anecdotal information suggests thatthis method costs only slightly morethan air-drying, due to the reducedcosts of treatment needed later (e.g.,flattening, treatment of tidelines, etc.).

Vacuum freeze-drying does notappear to affect the ability to treatartworks later—for example, reduc-tion of tideline stains is typically stillpossible and, in some instances, ismade easier after vacuum freeze-drying.

Disadvantages

Use is limited to artworks with thinlyapplied media and no surface coatings.

Due to the rapid drying system,materials may be overdryed, sohumidification after drying may benecessary.

The process cannot be interrupted toevaluate the materials.

VACUUM FREEZE-DRYING

Freezer drying of water damaged artifacts.

DAMAGE FROM

SMOKE, SOOT, AND PARTICULATE

MATTER

Damage caused by fires may be limited to smoke and soot. Heavy accumulations of particulate matter can also result fromvolcanic eruption, earthquake, or furnacemalfunction.Artworks on paper are seri-ously, possibly irreversibly, affected by thiskind of damage.Though salvaging sootyartworks should proceed as quickly as pos-sible, this can wait until wet materials arestable. Staff should assess the extent of theproblem, but should handle artworks nomore than is necessary, so that surface dirtdoes not become embedded in the fibers of the paper support.All cleaning proce-dures must be developed and supervised by a paper conservator.Appropriate proce-dures can reduce dirt and discoloration, butbecause of the absorbent nature of paper,some disfiguration may remain.

Soot is a hazardous substance, and itsprecise composition should be assessed byan industrial hygienist with experience inart materials and environments to determineappropriate safety precautions. Dependingon what materials were burned in the fire,lead or polychlorinated biphenyls (PCBs)may be present, requiring the services ofprofessional abatement workers.

Smoky odors can sometimes bereduced by providing air circulation around the artworks, by storing artworks in enclosures with zeolites (molecular trapsincorporated in the paper or paperboard),or by including zeolite-containing materi-als in existing enclosures. It is important tonote that although anecdotal evidence sug-gests that zeolites reduce odors, controlledresearch has not been done.This treatmentmay be most effective with small amountsof collection materials. Do not employozone treatments for odor mitigation;ozone is effective in reducing odors, but it also has a strong potential to degradepaper and media.

C O N S E R V A T I O N C E N T E R

for Art and Historic Artifacts264 South 23rd StreetPhiladelphia, PA 19103

215.545.0613Fax 215.735.9313

E-mail ccaha@ccaha.orgWebsite www.ccaha.org

© 2000, Conservation Center for Art andHistoric Artifacts (CCAHA), Philadelphia, Pa.

All rights reserved. Not to be reproduced without permission from the Conservation

Center for Art and Historic Artifacts.

Anne Downey and Mary Schobert, Senior Conservators

at the Conservation Center for Art and Historic Artifacts,

wrote this bulletin. The William Penn Foundation

provided funding for the design and printing of this

bulletin. Molly B.C. Ruzicka, copy editor, and Phillip

Unetic, designer, provided additional assistance.

ADDITIONAL

RESOURCES

TRAINING AND PROFESSIONALDEVELOPMENT

Knowledge and familiarity with disasterrecovery techniques can be gained throughtraining and educational seminars offeredby groups such as the Conservation Centerfor Art and Historic Artifacts. Paper conser-vators and allied professionals are encouragedto enlarge awareness of recovery techniquesby compiling and sharing anecdotal first-hand experience, organizing and participat-ing in salvage workshops, and promotingscientific research into recovery methods.

SUGGESTED REFERENCES

Building an Emergency Plan:A Guide forMuseums and Other Cultural Institutions.Compiled by Valerie Dorge and SharonJones. Los Angeles: Getty ConservationInstitute, 1999.

Conservation Center for Art and HistoricArtifacts. Managing a Mold Invasion:Guidelines for Disaster Response.Conservation Center Technical Leaflet 1.Philadelphia: Conservation Center for Artand Historic Artifacts, 1996.Available inEnglish and Spanish on CCAHA’s website:www.ccaha.org.

The Emergency Response and Salvage Wheel.Heritage Preservation for the National TaskForce on Emergency Response, 1997.Atext version is available in Spanish.Availableon Heritage Preservation’s website: www.heritagepreservation.org/programs/wheel1.htm.

National Park Service.“MuseumCollections: Emergency Planning.” Chap.10 and “Curatorial Care of Paper Objects.”Appendix J. in Museum Handbook, Part I -Museum Collections.Washington, D.C.:U.S. Government Printing Office. RevisedSeptember 1990.

Rossol, Monona.“Compliance inRecovery: Regulatory Requirements in theAftermath of Disaster.” AIC News 23 (5)(1998): 1, 4–7.

These general recommendations are intended to provide

practical guidance in the recovery of water-damaged

objects. The recommendations are intended as guidance

only, and CCAHA does not assume responsibility or

liability for any resulting treatment of water-damaged objects.

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Steal This Handbook:A Template for Creatinga Museum’s Emergency Response Plan.Columbia, S.C.: Southeastern Registrar’sAssociation, 1994.

Walsh, Betty.“Salvage Options for WaterDamaged Collections.” WAAC Newslettervol. 10, no. 2, May 1998. palimpsest.stan-ford.edu/waac/wn/wn10/wn10-2/wn10-202.html.

OTHER RESOURCES

Locating Conservators

American Institute for Conservation ofHistoric and Artistic Works (AIC)1717 K Street, NW, Suite 200Washington, DC 20006(202) 452-9545; Fax: (202) 452-9328e-mail: info@aic-faic.org; web site: aic.stanford.edu AIC provides free referral to conservators and various publications on collection care.

Regional Alliance for Preservation (RAP)www.rap-arcc.org

Health and Safety Information

Arts, Crafts & Theater Safety, Inc. (ACTS)181 Thompson Street, #23, New York, NY10012-2586; (212) 777-0062e-mail:ACTS@caseweb.comwww.caseweb.com/acts/