Label removal from deteriorated leather-bound books

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Label removal from deteriorated leather-boundbooksRobin O'Herna & Ellen Pearlsteinb

a National Museum of the American Indian, Cultural Resources Center, 4220 Silver HillRoad, Suitland, MD 20746, USAb UCLA, A210 Fowler Building, Los Angeles, CA 90095-1510, USA. Email:Accepted author version posted online: 12 Jul 2013.Published online: 29 Nov 2013.

To cite this article: Robin O'Hern & Ellen Pearlstein (2013) Label removal from deteriorated leather-bound books, Journalof the Institute of Conservation, 36:2, 109-124, DOI: 10.1080/19455224.2013.815123

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Robin O’Hern and Ellen Pearlstein

Label removal from deteriorated leather-boundbooks

Keywords

book conservation; label removal; pressure sensitive labels; leather bindings; poultices

Pressure-sensitive labels for library applications are specified to includepermanent materials in both the substrate and the adhesive, to be able towithstand temperature extremes, and to avoid adhesive transfer andunwanted removal.1 These labels are differentiated from those in commer-cial applications where ephemerality may be tolerated.2 Permanent labelsare, however, recommended only in the case of circulating collections,and ‘. . . are not intended for use on rare or highly valuable materials’.3 Itis common to encounter instances in libraries and museums where a collec-tion’s status changes. The system for tagging or labelling that was at onetime appropriate is no longer the case, and the labels need to be removed.

The authors conducted a comparative study of over 20 different tech-niques for the removal of pressure-sensitive labels from a series ofleather-bound books from a university library. These books were part ofthe university’s pre-1800 collection but not in the special collection. Theyhad been on open shelves until the 1970s or 1980s when they weremoved to closed stacks but remained in circulation. In the 1990s, the pre-1800 collection was moved again to an off-site storage area and blanklabels were applied in preparation for placing bar codes on the books.Bar-coding of books in off-site storage enables them to be shelved by size,not by call number, for space efficiency. However, following a policychange in 2007–08, the pre-1800 books were moved to special collectionsand the new bar codes were instead applied on flags inserted into thebooks.4 The blank bar code labels were now redundant and needed to beremoved from the books. Since these labels had most likely been selectedfor their permanence, had been applied to deteriorated leather, and hadbeen on the books since the 1990s, they presented an opportunity tocompare different techniques for the labels’ removal.

Most of the literature on tape and label removal is written for paperobjects.5 In terms of other materials, Chester and Eastop describe theremoval of adhesive staining caused by tape applied to a silk bannerthrough use of a suction table.6 Navarro presents a technique for labelremoval from glass and ceramics using a blotter paper and Gore-texw

(polytetrafluoroethylene) sandwich.7 Recently, Summerour et al. discussedremoving black photo tape from caribou hair using dry ice followed byGroomstick to reduce adhesive residue.8 Literature on the removal oflabels from leather is lacking. The removal of tape and labels from leatheris distinctly different from removing tape from paper or ceramic surfaces.The leather substrate prohibits the application of solvents from thereverse, which could be considered for a paper artefact. Additionally, theleather surface is fragile and can be separated easily or damaged, unlikethe surface of stable glass or ceramic objects. This is especially the casewith sheepskin bindings, where the grain layer tends to delaminate fromthe corium.9

(Received 28 August 2012; Accepted 4 June 2013)

1 Library of Congress PreservationDirectorate, ‘Specifications for PressureSensitive Adhesive Labels Applicationto Single Paper Sheets and Text Pagesof Bound Books for Use in ThermalTransfer Prints,’ Specification Number700-714–09, http://www.loc.gov/preservation/resources/specifications/specs/700-714_09.pdf (accessed August19, 2012).

2 Michele H. Youket, email to Cons Dist-List mailing list, April 15, 2003, http://cool.conservation-us.org/byform/mailing-lists/cdl/2003/0439.html (accessedAugust 19, 2012).

3 Library of Congress, ‘Specificationsfor Pressure Sensitive Adhesive,’ 1.

4 Kristen St. John, email message to theauthor, August 23, 2012.

5 See, for example, Francine Gauthierand Denise Allard, ‘The ContinuingSaga of Pressure-Sensitive Adhesives’,IIC CG Bulletin 19 (1994): 19–22; JaneDalley, ‘Pressure-Sensitive Tapes: TheirBehaviour and Removal, as Illustratedby a Case Study’ (presented at the Con-servation of Historic and Artistic Workson Paper, Ottawa, Canada: CanadianConservation Institute, 1988), 39–46;Anja Koschel, ‘Abnahme Von Klebes-treifen: Untersuchungen Zum EinsatzVon Carbopol-Gelen Beim Ablosen VonFilmoplastw-Produkten [Removal ofPressure Sensitive Adhesive Tape: theUse of Solvent Gel Carbopol toRemove Filmoplastw Products]’, Mutar-gyvedelem 32 (2007): 141–8; ElissaO’Loughlin and Linda Stiber, ‘A CloserLook at Pressure-Sensitive Adhesive

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The aim of this research was to evaluate different techniques for theremoval of similar labels from the leather-bound books. For this project, asuccessful technique needed to meet the following three criteria. First, aswith any treatment, it should not cause damage to the object or make itmore susceptible to damage in the future. Therefore, the treatmentshould not cause visible disruption to the leather surface, such asthrough loss of the top layer of fibres, nor any colour changes, or tidelines caused by mobilizing original or applied materials. Secondly, theresearch aimed to determine whether it was possible to develop a techniquethat could be implemented by the library’s technicians. It was important forthe technicians to be able to apply the technique successfully on othercollections in addition to this series of 33 books. Finally, the techniquehad to involve non-hazardous materials and be able to be carried out in anon-laboratory setting. The space in which label removal on books wouldbe carried out by the technicians had limited ventilation and, therefore,the health and safety requirements of the techniques were an importantconsideration.

This project was undertaken by the first author as a research activityduring graduate school and supervised by the second author. A previousclass of students had tested several techniques as a course assignmentand the work of the first author repeated many of those tests while buildingon their findings.10

Previous approachesPressure-sensitive tapes and labels have similar properties and a review ofthe literature on both of them is informative. Pressure-sensitive tapes aremade up of four layers of material, whereas labels generally have threelayers. In tape, these layers are the adhesive, the primary coat (or keyingcoat) to ‘bond the adhesive coating to the carrier’, the carrier (orbacking), and the release coat.11 Labels have the lower three layers(adhesive, primary coat and carrier) and not the top release coating.O’Loughlin and Stiber discuss how the adhesive is made up of several com-ponents—including elastomers, tackifiers, plasticizers, antioxidants, andfillers—and how the composition of commercial products is subject tochange.12 The tape or label carrier can be made of a variety of differentmaterials, such as paper, metal foil, fabric, cellophane, cellulose acetate,polyvinyl chloride, polyester, polypropylene or crepe paper fillers.13

A number of different techniques for tape or label removal are discussedin the conservation literature. These include peeling or shaving with ascalpel, lifting with a spatula, changing adhesive properties with dry iceor a tacking iron, and reducing adhesion with rubber erasers. Additionaloptions involve solvents applied directly or through the use of solventchambers, poultices and immersion.14 Carbopol (a polyacrylic acidgelling agent) and Ethomeen C-25 (Polyoxyethylene(15) coco amine) arementioned as options for the removal of pressure-sensitive tapes byKoschel.15 Warda et al. researched the effect of solvent gels on paper,which would be an important consideration when using them to removepaper labels.16 The process of making solvent gels is discussed in severalarticles and books.17

Description of the booksThe leather books (each measuring approximately 16.5 × 10.3 × 2.9 cm)comprise part of a series entitled ‘Observations sur les Ecrits Modernes’,published between 1735 and 1743.18 Each of the 33 books in the serieswas very similar in terms of construction and condition. The book coverswere board bound in leather with marbled end paper and five raisedbands on the spine. The spines of the books had two very thin red dyed

Tapes: Update on Conservation Strat-egies’, ed. Sheila Fairbrass (presentedat the Institute of Paper Conservation,Manchester: Institute of Paper Conser-vation, 1992), 280–7; and MerrilyA. Smith et al., ‘Pressure-SensitiveTape and Techniques for Its Removalfrom Paper’, Journal of the American Insti-tute for Conservation 23 (1984): 101–13.

6 Allison Chester and Dinah Eastop,‘The Problem of Common SolubilityParameters: The Removal of NaturalRubber Adhesive Residues from aPainted Silk Banner’ (presented at theResins Ancient and Modern conference,Aberdeen: Scottish Society for Conser-vation & Restoration, 1995), 47–52.

7 Juanita Navarro, ‘Removing PaperLabels from Ceramics and Glass’, The

Conservator 21 (1997): 21–7.

8 Rebecca Summerour et al., ‘RemovingModern Accretions: Hot-Melt Adhesive,Chewing Gum, and Pressure SensitiveTape’ (Poster at the 41st AnnualMeeting of the American Institute forConservation, The Contemporary inConservation, Indianapolis, IN, May29–June 1, 2013).

9 David Pearson, John Mumford, andAlison Walker, Bookbindings (London:The Preservation Advisory Centre, TheBritish Library, 2010), 7, http://www.bl.uk/blpac/pdf/bookbindings.pdf(accessed July 23, 2013).

10 Ellen Pearlstein et al., ‘AdhesiveReversal for Book Bindings LaboratoryReports’ (laboratory report, UCLA/

Getty Program in the Conservation ofEthnographic and ArchaeologicalMaterials, University of California, LosAngeles, 2008).

11 Dalley, ‘Pressure-Sensitive Tapes’;Smith et al., ‘Pressure-Sensitive Tape’.

12 O’Loughlin and Stiber, ‘A CloserLook’.

13 O’Loughlin and Stiber, ‘A CloserLook’; Smith et al., ‘Pressure-SensitiveTape’.

14 Dalley, ‘Pressure-Sensitive Tapes’;O’Loughlin and Stiber, ‘A CloserLook’; Smith et al., ‘Pressure-SensitiveTape’.

15 Koschel, ‘The Use of Solvent Gel’.

16 Jeffrey Warda, Irene Bruckle, AnikoBezur, and Dan Kushel, ‘Analysis ofAgarose, Carbopol, and Laponite GelPoultices in Paper Conservation’,Journal of the American Institute for Con-servation 46 (2007): 263–79.

17 Chris Stavroudis and Sharon Blank,‘Solvents & Sensibility’, WAAC Newslet-

110 O’Hern and Pearlstein

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leather labels attached with an adhesive in the second and third panels.There was gold tooling along the spine and on the exterior edges of theleather cover. The sixth panel of the spine was painted with black painton which the accession number was hand-written in white. All threeedges of the text block (top, fore-edge and bottom) were sprinkled withsmall spots of red and stamped with the words identifying the owninglibrary. The white pressure-sensitive labels, to be removed, were locatedin the upper left corner of the front cover on each book.

As part of the documentation prior to treatment, each book was exam-ined and photographed using ultraviolet (UV) induced visible fluor-escence. No fluorescing tide lines were observed around the labels beforetreatment. The covers of the books had brush or wipe marks of a slightlyfluorescing material on them, suggesting that they may have been coatedor treated at some point. The coating may not have been evenly appliedover the surface or similarly applied across different volumes, whichcould affect the way solvents would interact with the leather. Finally, theleather bindings transferred fibrous material upon contact, an indicationthat the leather was fragile and deteriorated.

Leather characterizationLeather is a tanned skin whose source animal and methods of processingcan be characterized by analysis and observation. Composed of interwovencollagen fibres, leather has a distinctive follicle pattern specific to the sourceanimal.19 The follicle pattern is visible in the grain layer on the hair side ofthe leather. Below the grain layer is the corium layer followed by the fleshlayer. The leather on the books was investigated to characterize the folliclepattern, grain structure and tanning method. Shrinkage temperature andpH were measured to assess condition.

The cross-section of the leather revealed a corium layer and a grain layer,but not the layer closest to the flesh, indicating that the processing historyincluded splitting or thinning. The follicle pattern visible in the grain layerclosely resembled that of sheepskin (Fig. 1).

Fig. 1 A detail of the follicle pattern on the leather under an optical microscope.

ter 11, no. 2 (1989): 2–10; Chris Stavrou-dis, ‘Carbopol 934; Ethomeen C25;Ethomeen C12; Armeen CD; Now Avail-able from Conservation Materials, Ltd,’WAAC Newsletter 12 (1990); Chris Stav-roudis, Tiarna Doherty, and RichardWolbers, ‘A New Approach to CleaningI: Using Mixtures of Concentrated StockSolutions and a Database to Arrive at anOptimal Aqueous Cleaning System’,WAAC Newsletter 27, no. 2 (2005):17–28; and Richard Wolbers, CleaningPainted Surfaces: Aqueous Methods(London: Archetype Publications, 2000).

18 Observation sur les ecrits modernes,Vol. 1–34 (Paris: Chaubert, 1735–43).

19 Aline Angus, ‘An Introduction to theTypes of Tannages Used on Ethno-graphic Leather’, ed. Margot M. Wright(presented at The Conservation of Fur,Feather, and Skin: Seminar Organisedby the Conservators of EthnographicArtefacts at the Museum of London,Archetype Publications, 2000).

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Two spot tests were used to identify the tanning procedure used on theleather. The first, a ferric sulfate test, differentiates between vegetableand non-vegetable tannins. The second, a Vanillin test, differentiatesbetween condensed and hydrolysable vegetable tannins.20 The type oftanning process used on the leather affects the way that it responds toenvironmental changes and the way it ages. Using the testing method-ology described by Odegaard et al. on samples of leather fibres thathad separated from the books during examination, the ferric sulfatetest for vegetable tannins gave a positive result for vegetable tanninsand the Vanillin test gave a positive result for hydrolysable vegetabletannins.21

The shrinkage temperature of a sample of leather provided an indicationof the hydrothermal stability of the leather, conferred by the tanningmethod used and the level of deterioration in the leather. To conduct thetest, a few leather fibres were held in water in a depression slide on a con-trolled hot stage (Physitempw Thermal Microscope Stage) and observedunder a binocular microscope. Starting at 208C, the temperature was gradu-ally increased while the sample was observed, and the temperature range atwhich visible shrinkage occurs was recorded. Untanned leather, orrawhide, will normally shrink at between 60 and 658C. Tanning processesgenerally raise the shrinkage temperature. However, as the collagenfibres deteriorate, the shrinkage temperature decreases.22

The shrinkage temperature range for the three samples taken wasbetween 25 and 378C. The shrinkage temperature range of undegraded veg-etable tanned leather is 75–808C. Since the leather fibre samples started toshrink at 258C, this indicated that the leather was very degraded. The lowshrinkage temperature of the fibres also suggested that the use of heat toremove the labels would be a poor choice for treatment.

The condition of the leather was also evaluated by measuring the surfacepH. A pH of less than 2.8 can indicate the presence of red rot, a condition inwhich there is hydrolytic degradation of collagen resulting from acidsintroduced during manufacture or exposure to acidic pollutants.23 ThepH of the leather in the bindings averaged 4.0–4.5 when measured byplacing a few fibres on each square of slightly damp pH indicator teststrips (ColorpHast 0–14 and ColorpHast 0–6). The pH of the leather,while acidic, was within the expected range for leather. However, the detec-tion of surface pH, while avoiding sample removal, was limited by the ratioof leather to water and it was therefore difficult to make definitive state-ments about the results of the pH test.

In summary, the results of these investigations indicated that the leatherwas a very degraded sheepskin that had been tanned with hydrolysablevegetable tannins.

Label characterizationThe label was characterized by microscopic examination of the paper com-ponent as well as through the use of Fourier transform infrared spec-troscopy (FTIR) and solubility testing on samples of the adhesive. Thepaper component of the label was a network of translucent white fibreswith several reddish or blue fibres mixed in (Fig. 2). It seemed somewhatporous and soft with a surface texture, suggesting that the paper wasnon-calendared. The fibres were not very coherent and separated easilywhen probed. The adhesive was a clear material which was very soft,tacky and stringy at room temperature. It was visible around the edges ofsome of the paper labels. The label was firmly adhered to the leather, andit was difficult to remove a sample of the adhesive without removingfibres from the leather surface.

20 C. van Driel-Murray, ‘Practical Evalu-ation of a Field Test for the Identificationof Ancient Vegetable Tanned Leathers’,Journal of Archaeological Science 29, no. 1(2002): 17–21; and Dorte V. Poulsen,‘Presentation and Evaluation of SpotTests for Identification of the TanninType in Vegetable Tanned Leather’, vol.II (presented at the ICOM Committeefor Conservation, ICOM-CC: 13th Trien-nial Meeting, Rio de Janeiro: James andJames, 2002), 792–7.

21 Nancy Odegaard, Scott Carrol, andWerner S. Zimmt, Material Characteriz-ation Tests for Objects of Art and Archaeol-

ogy, 2nd ed. (London: ArchetypePublications, 2005).

22 Angus, ‘Types of Tannages’; andRene Larsen, ‘Experiments and Obser-vations in the Study of EnvironmentalImpact on Historical Vegetable TannedLeathers’, Thermochimica Acta 365(2000): 85–99.

23 Roy Thomson, ‘Testing Leather andRelated Materials’, in Conservation ofLeather and Related Materials, ed.Marion Kite and Roy Tomson (London:Butterworth-Heinemann, 2006), 58–65.



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A sample of the adhesive from one of the labels was removed and ana-lysed using FTIR.24 The results of the analysis indicated that the adhesivewas very similar to several acrylic emulsions, but did not match one par-ticular emulsion exactly.25 The adhesive was most similar to Lascaux 360acrylic emulsion, Lascaux 480 HV acrylic emulsion, Plextol D514 acrylicemulsion and Rhoplex AC-507 emulsion, which are butyl methacrylatesand tacky at room temperature.26

To test the solubility of the label adhesive, small samples were removedfrom the edges of the label on volume 13 and placed on glass slides. A smalldrop of solvent was added to the sample, which was then observed underthe microscope. To test the effect on the leather of the solvents that mosteffectively solubilized the adhesive, micro swabs of cotton wool wrappedaround a bamboo skewer were created. A lightly moistened swab washeld gently on the leather for 10 seconds and then visually evaluated.

The adhesive was found to be insoluble in water, but did soften and swellimmediately upon the addition of ethanol and acetone. However, bothethanol and acetone caused slight darkening and tide lines on the leather.Ethyl acetate solubilized the adhesive and left no tide lines on the leatherbinding. None of the other components of the books were soluble inethyl acetate, with the exception of the white call number on the spine.

Label removal experiments and resultsA number of different techniques for label removal were tested.27 Each ofthe techniques was evaluated based on its ability to remove the labelwithout damage to the leather, the ease of use of each technique, andhealth and safety implications. Each of the books was re-examined aftertreatment with UV-induced visible fluorescence.

1 Mechanical techniquesMechanical removal of labels can be performed in one step or, more com-monly, in two steps when the paper carrier is removed followed by the

Fig. 2 Detailed image of the paper label.

24 The adhesive’s spectrum wasacquired over the range of 4000–500cm21 and compared with spectra inthe IR database and the Infrared andRaman Users Group database (IRUG),http://www.irug.org/ed2k/search.asp(accessed 3 May, 2013). The analysis wasundertaken on a Perkin-Elmer Spec-trum One Infrared spectrometer in Atte-nuated Total Reflectance (ATR) modewith a Zn–Se crystal.

25 IRUG Spectral Database Edition 2000http://www.irug.org/ed2k/search.asp(accessed 3 May, 2013).

26 Pearlstein et al., ‘Adhesive Reversalfor Book Bindings’.




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adhesive layer. Removing the entire label usually involves separating theadhesive from the substrate layer using a tool like a spatula, bambooskewer or scalpel. An additional method tested for this project was usingmechanical abrasion to remove the label.

Several different mechanical tools were tested to remove the label,including bamboo skewers cut to form thin spatulas, thin metal spatulas,and scalpels with number 10 and 15 blades. The tools were slid gentlyalong the edge of the label, almost parallel with the surface of thebook. The goal was to be able to have the tool work its way betweenthe adhesive and the leather surface. Unfortunately, with all toolstested the tackiness of the adhesive and its adhesion to the leathermade it impossible to separate the two without removing the top layerof the leather. The adhesive was also so tacky that it stuck to each ofthe tools (Table 1).

Using a very sharp scalpel held almost parallel to the book surface, thepaper component of the label could be removed with the remainingadhesive reduced by another technique (Fig. 3). Residual adhesive actedas a barrier against damage to the leather by the scalpel. However, anytug on the adhesive—which occurred frequently due to its tackiness—caused separation of the top layer of the leather. Once separated, theadhesive layer promoted further delamination of the leather. Additionally,the edges of the label were particularly challenging to remove without dis-turbing the leather surface. Reducing the paper component without dama-ging the leather was difficult and required very good hand skills but itcould be successful. Follow-up attempts to remove the adhesive (bybrush, swab, and cellulose poultice with ethyl acetate as describedbelow) resulted in approximately 50% of the leather nap being removedbecause of damage during reduction of the paper.

The Micromeshw (a silicon carbide or aluminium oxide abrasive cloth)enabled abrasion of the paper carrier until it was almost entirely reduced(Fig. 4). Although this technique did enable the reduction of the paper com-ponent, it had several significant drawbacks. It was difficult to reduce thevery edges of the label without damaging the leather. The flat labelsurface was actually uneven, resulting in the abrasion of some areasmore quickly than others; and the adhesive snagged on the micromeshpulling up the leather surface.

2 Temperature manipulationSometimes manipulating the temperature of the adhesive can alter its phys-ical properties and enable its removal. For this experiment, both loweringand raising the temperature of the label and its adhesive were testedusing dry ice and a hot spatula (Table 2).

Table 1 Methodology and observations for tests involving mechanical label removal methods.

Technique Methodology Observations

Metal spatulas,bamboo skewers

Inserted between adhesive and leather surface. The tackiness of the adhesive and its adhesion to the leather madeit impossible to separate the two without removing the toplayer of the leather.

Scalpel Thin layers of the paper component removed. Required a sharp scalpel used almost parallel to the surface.The paper component of the label could be reduced leaving

behind the adhesive. Frequent snagging of the blade on theadhesive caused separation of the top layer of leather. The labeledges were particularly difficult to remove.

Abrasion Paper component abraded with Micro-meshw

(a silicon carbide or aluminum oxide abrasivecloth).

Reduced paper layer. Pulled away the top layer of leather,snagged on adhesive, uneven abrasion.



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Several techniques involving dry ice (solid carbon dioxide) and coolingthe label were tested to determine whether simply cooling the labelwould reduce the tackiness and adhesion of the adhesive. The first tech-nique involved placing the dry ice directly on the label and keeping itcovered for five and 15 minutes. The dry ice was removed and attemptsto lift the label with tweezers also removed the leather surface. In asecond technique, the label was heated to 708C using a hot spatula andthen dry ice was applied for five minutes. This caused more leather to beremoved with the label. Finally, a combination of solvent and cooling wastested by applying a Laponite RD (sodium magnesium lithium silicate)

Fig. 3 Removal of the paper carrier with a scalpel. (a) Before treatment. (b) During treatment.The upper left area of the label during treatment shows where the adhesive pulled away thetop of the leather.

Fig. 4 A label during removal with Micromeshw.



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poultice with acetone for 15 minutes followed by dry ice, which again didnot manage to remove the label. While these techniques did not causesurface staining or visible damage to the leather, leather fibres wereremoved with the label and the techniques were deemed unsuccessful.29

In addition to cooling the label, heat was also tested as a removal tech-nique (Fig. 5). This test was undertaken prior to the fuller characteriz-ation of the leather by shrinkage temperature measurement. Theresults of the shrinkage temperature test indicated that using heat nearthe leather was not recommended, as it would cause shrinkage and irre-versible change to the leather. For this technique, a hot spatula wasplaced on the label at temperatures up to around 658C. This techniquedid not work well. As in the shrinkage temperature test, the heatcaused the leather to shrink and increased adherence between theadhesive and the leather.30

3 Direct application of solventsSince the tackiness of the adhesive made it difficult to remove the labelwithout also removing the top surface of the leather, solvent-based tech-niques were investigated. Solvents can be introduced either through thepaper carrier or along the edge of the label by brush, swab, or in avapour chamber.

Earlier solvent testing had identified acetone and ethanol as potential sol-vents for the label adhesive, although both evaporated too quickly to permiteffective label removal and caused tide lines on the leather. Acetone, 1:1

Fig. 5 A label during removal using a hot spatula.

Table 2 Methodology and observations involving temperature manipulation removal methods.

Technique28 Methodology Observations

Dry ice(solid carbon dioxide)

Dry ice applied to the label alone, or following theapplication of heat, or a poultice.

No staining of or damage to the leather. Removed toplayer of leather.

Hot spatula Hot spatula applied to the label. Using heat caused increased fusion betweenadhesive and leather.

28 The testing of these techniques wasundertaken by Pearlstein et al.,‘Adhesive Reversal for Book Bindings’.





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xylene: acetone, and ethyl acetate were tested by rolling a swab on the labelfor five minutes under a fume hood. However, the solvent mixtures did notcause any change to the label and did not enable the label’s removal.32 Itmay be that this technique for applying the solvent through the papercarrier did not allow it to successfully penetrate through the paper labeland interact with the adhesive (Table 3).

Tests applying ethyl acetate by brush to the edge of the label were slightlymore successful. The solvent was able to interact with the adhesive as it didnot have to pass through the paper carrier and primary layer. However,ethyl acetate evaporated very quickly which made it difficult to separatethe adhesive from the grain layer. When the brush dried out, it wouldcatch on the tacky adhesive and pull on the top layer of leather.

With the goal of enabling the solvent to interact more with the adhesive,the book was placed for 30–60 minutes in a vapour chamber made from asealed polyethylene bag containing three beakers filled with approximately50 ml of ethyl acetate. Solvent tests had been undertaken on all the other com-ponents of the book and only the call number had demonstrated any sensi-tivity to the solvent. As a result, the call number was closely monitored whilethe object was in the vapour chamber. The vapour chamber reduced thetackiness of the adhesive, but this soon returned when the book wasremoved from the chamber. Attempts to remove the label while the bookremained in the vapour chamber were difficult because of the challenge ofmaintaining the vapour chamber without restricting access to the object.This technique on its own was not successful at softening the adhesiveenough to enable a separation between the adhesive and the leather surface.

One of the concerns with using a solvent is the potential for it to causemovement of soluble components in the structure of the leather. Researchby McCrady and Raphael into the effects of dressings on leather indicatedthat solvents can cause leather to swell and possibly distort and alter thesurface finish, in addition to moving soluble components in the leather.33

Examination of the surface of the books using UV-induced visible fluor-escence found some areas with a possible coating that could affect theway solvents interact with the leather. A concern with the use of solventsor water was the creation of tide lines at the wet–dry boundary. Eusmanfound that tide lines on paper had more peroxides present, which acceler-ated cellulose degradation, and that tide lines fluoresce under UV radiation,even those that cannot be seen in visible light.34 Although leather is madefrom collagen fibres not cellulose, UV radiation can still provide infor-mation about the presence of tide lines, adhesives and coatings onleather. Examination of the book covers after treatment found no fluores-cing tide lines or disruption to the fluorescence.

4 Poultice application of solventsPoultices can help to increase the interaction between solvent and adhesive,as well as to draw the solubilized adhesive material into the poultice—and

Table 3 Methodology and observations for tests involving solvent removal methods.

Technique Solvent Methodology Observations

Cottonswab31

Xylene: acetone1:1

Swab with solvent rolled on labelsurface.

No damage to the label. No change to the label. Solventtoxicity required fume hood.

Cotton swab Ethyl acetate Swab with solvent rolled on labelsurface.

No tide lines developed on the leather. Solvent did notpenetrate label to reach the adhesive.

Vapourchamber

Ethyl acetate Book placed in sealed polyethylene bagwith three beakers of ethyl acetate for30–60 minutes.

Reduced tackiness of the adhesive. Tackiness of the adhesivereturned quickly once removed from the chamber. Difficultto work on the object without solvent loss while it was invapour chamber.

31 The testing of this technique wasundertaken by Pearlstein et al.,‘Adhesive Reversal for Book Bindings’.


33 Ellen McCrady and Toby Raphael,‘Leather Dressing: To Dress or Not toDress,’ National Park Service Conserve OGram 9, no. 1 (1993): 1–3.

34 E. Eusman, ‘Tideline Formation inPaper Objects: Cellulose Degradationat the Wet–Dry Boundary’, ConservationResearch, Studies in the History of Art,monograph series II, 51 (1995): 11–27.



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not into the leather. Two of the concerns with using a poultice to apply thesolvent included even application and easy removal of the poultice. As partof this research, several different poultice vehicles for the removal of thelabels were tested, including cotton wool, cellulose fibres, PVA (modifiedpolyvinyl alcohol) sponge, attapulgite (hydrated aluminium-magnesiumsilicate), and blotter paper (Table 4).

Solvent gels were tested because it was hoped that they would maintaingood contact with the label during mechanical removal. Several differenttypes of gels were used, including Laponite RD, methyl cellulose, and aCarbopol 940/Ethomeen C-25 gel. The application of gels may not beappropriate for labels that have writing on their surface as the gel may solu-bilize the inks. However, the labels in this study were blank.

The cotton wool poultice was made by dampening the cotton wool withacetone. This was applied directly on top of the label and covered with asmall Petrie dish for 20 minutes to create a localized solvent chamber. Asection of the label was removed with a scalpel and the residual adhesiveat the interface between leather and label reduced by swabbing withacetone. This technique caused areas of the label directly in contact withthe poultice to curl away from the leather. However, the result was incon-sistent and uneven, and tide lines developed in the leather.

The cellulose powder poultice was tested with acetone and 1:1 acetone:ethanol solvent mixtures. A 0.5cm thick layer of the cellulose powder satu-rated with acetone was placed on the label. The poultice was covered with asmall Petrie dish to slow the evaporation of the solvent. Over the course ofseveral minutes, the label was tested to determine whether it could beremoved. This poultice was easy to apply and the solvent wicked into thelabel quickly without saturating the leather. However, it did not enableremoval of the label without also removing the upper surface of theleather, and the timing of removal was important.35

The cellulose powder poultice was also tested with ethyl acetate and ablotter paper spatula. In this method, a cellulose powder poultice saturatedwith ethyl acetate was placed on top of the label. A rectangular strip ofblotter paper was then dipped into the ethyl acetate and nudged gentlyalong the edge of the label. Once the label started to separate, the blotterpaper was gently nudged along the interface between the label and theleather. Occasionally, the leather nap would start to separate from the cover.When this happened, a scalpel was used to separate the adhesive from theleather nap. Then the blotter paper spatula was carefully reintroduced to thearea to continue separating the label from the leather surface. A piece of siliconerelease Mylar was placed on top of the section of the leather where the labelhad been removed, to prevent the label from accidentally re-adhering. Thistechnique was very slow. It was also difficult to conduct prolonged workusing a respirator. The advantages of this technique were that no tide linesoccurred, and about 50% of the leather’s surface remained intact, which wasbetter than the other techniques. With practice, it was considered that it maybe possible to remove the label without also removing any of the leather nap.

PVA sponges were tested as possible poultices because they are capableof holding large quantities of liquid in a restricted area.36 These sponges canbe used with water and organic solvents. A small section of the sponge wascut off and saturated with acetone. The solvent-saturated sponge wasapplied directly on top of the label and a small Petrie dish coveringcreated a localized solvent chamber for 20 minutes. This technique didnot leave tide lines but the adhesive did not swell or soften. This is possiblybecause the sponge retained the acetone and did not allow the solvent topenetrate through the label.37

Attapulgite was tested as a poultice material, as it has been used success-fully for removing stains from ceramics. In this case, the attapulgite was


36 For the current application, theauthors acknowledge that PVAsponges are commercial products thatmay contain ethyl acetate soluble com-ponents.




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saturated with 1:1 acetone: ethyl acetate and applied over a small piece ofReemay paper that had been pre-wetted with acetone. The poultice wascovered and left for three to five minutes. To remove the label, a bambooskewer was used to lift the edge and an acetone swab helped to separatethe stringy adhesive from the leather surface. This technique did enablethe removal of the label but resulted in the development of white spotsand tide lines on the leather.39

Borrowing a technique used in paper conservation, a blotter paper sand-wich was applied to try and remove the label. In this technique, a layer ofGore-texw (polytetrafluoroethylene) was placed over the label, followed bya piece of blotter paper cut to the size of the label and saturated with ethylacetate. The area was then covered with a Petrie dish and the label wastested at periodic intervals to determine whether it could be easily

Table 4 Methodology and observations for tests involving poultice application of solvents.

Technique38 Solvent Methodology Observations

Cotton poultice∗ Acetone Poultice applied on top of label and coveredwith Petrie dish.

Areas of label directly in contact with thepoultice curled away from the leather.Result was inconsistent and uneven. Tidelines developed.

Cellulose fibres∗ 1:1 acetone:ethyl acetate

Poultice applied over a small piece of Japanesetissue paper (kozo); label removedmechanically and adhesive residue reducedwith acetone swab.

Label could be removed with minimal damageto the leather surface. Adhesive residuesremained. Acetone caused tide lines.

Cellulose fibres∗ Acetone Poultice applied on top of label and coveredwith Petrie dish.

Easy to apply. Solvent wicked into the labelquickly without saturating the leather.Removal of label resulted in damage to theupper surface of the leather. The timing ofremoval was critical.

Cellulose fibres withblotter paperspatula

Ethyl acetate Cellulose fibre poultice saturated with ethylacetate applied on top of label; rectangularstrip of blotter paper dampened with ethylacetate inserted between adhesive andleather.

Good separation between adhesive and leathersurface. No tide lines developed. Very slow.Difficult to control if the nap started toseparate from the leather.

PVA sponges∗ Acetone Solvent-saturated sponge placed directly ontop of label and covered with a Petrie dish.

Poultice was easy to apply. No tide linesdeveloped. Adhesive did not swell orsoften.

Attapulgite(hydrousmagnesium-aluminium silicate)∗

1:1 acetone:ethyl acetate

Solvent-saturated attapulgite applied oversmall piece of Reemay (spunbondedpolyester) pre-wetted with acetone.

Label could be removed with minimal damageto the leather. Caused white spotting onleather. Tide lines developed.

Blotter paper Ethyl acetate Blotter paper saturated with ethyl acetateplaced over layer of Gore-texw on the label,and covered.

Easy to apply. Difficult to remove label whilemaintaining contact with the blotter. Tidelines developed where pressure was put onthe blotter paper.

Laponite RD∗ 20% acetone Laponite applied over a piece of Japanesetissue paper on label.

Gel caused adhesive to swell and softenslightly. Mechanically lifting the label with aspatula removed bits of the grain layer.

Laponite RD∗ 1:1 acetone:ethyl acetate

Laponite applied over a piece of Reemay paperand covered.

Label lifted away from the leather. Removingthe label caused losses to some of the grainlayer.

Laponite RD∗ 1:1 water :acetone andethyl acetate

Laponite applied over a piece of Japanesetissue paper on label.

Label could lift away from the leather. Theadhesive was very sticky. Gel stainedleather where it came into contact. Tide linesdeveloped.

Methyl cellulose∗ 20% acetone Laponite applied over a piece of Japanesetissue paper on label.

Not effective as the methyl cellulose acted asan adhesive.

Carbopol 940/

Ethomeen C-25Acetone Solvent gel applied over a piece of Japanese

tissue paper on the label and covered.Easy to apply and keep contained on the label.

No tide lines developed on the leather.Adhesive pulled away the upper layer ofleather during removal. Tide line developedon the label.

38 The testing of the techniques aster-isked was undertaken by Pearlsteinet al., ‘Adhesive Reversal for Book Bind-ings’.




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removed. This technique was unsuccessful because the ethyl acetate sof-tened the adhesive for a only short period of time. Once the solvent evap-orated, the adhesive became tacky again. Therefore, maintaining contactbetween the blotter paper and the label was important for maintainingthe softened adhesive but made it difficult to actually remove the label.There was no difference between leaving the poultice on for two or fiveminutes, as the solvent’s effect on the adhesive was almost instantaneous.

While Laponite RD is traditionally used as a gel for water, small amountsof some solvents can also be incorporated. One of the concerns with using aLaponite gel on the leather was the amount of water used to make the gel.Since the shrinkage tests indicated that the leather would react to water atclose to room temperature, a concern was that the application of water tothe surface of the leather may cause irreversible shrinkage. In the firsttrial, a 5% w/v Laponite gel with 20% acetone (by volume) was appliedover a small piece of Japanese tissue paper that was pre-wetted withacetone. The gel was left on for 20 minutes. This technique caused theadhesive to swell slightly where it was in contact with the solvent gel,but mechanically lifting the label with a spatula removed part of the toplayer of the leather. The second technique used Laponite with water,acetone and ethyl acetate. The Laponite was swelled with a 1:1 water:acetone solution and then ethyl acetate was added to the gel until itbecame saturated. The solvent gel was applied over a small piece of kozopaper that was pre-wetted with acetone. The poultice was covered withacetate film and left for five minutes after which the label was lifted withtweezers. The adhesive became somewhat stringy and the threads ofadhesive were cut with a scalpel. With this technique, the label could beremoved all at one time, but the adhesive remained very tacky, the gelstained the leather where they came into contact, and tide lines devel-oped.40

A mixture of 5% w/v methyl cellulose with 20% acetone by volume wasalso tested. The methyl cellulose gel was applied over a small piece of Japa-nese tissue paper that was pre-wetted with acetone. Japanese tissue paperwas used to enable a better removal of the gel. The methyl cellulose was lefton the label for 20 minutes. This technique was not effective as the methylcellulose acted as an adhesive and was difficult to remove.41

Fig. 6 Label removal using Carbopol 940/Ethameen C-25 acetone gel. (a) Before treatment.(b) During treatment. The black rectangle indicates the section of the label removed with thesolvent gel.





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The final solvent gel systems tested were two Carbopol 940/Ethomeen C-25 gels with ethyl acetate and acetone (Fig. 6). Acetone was chosen as onesolvent because of its moderate success at solubilizing the adhesive andthe ease of making an acetone gel. The acetone gel was mixed in accordancewith the recipe published by Stavroudis.42 The solvent gel was applied tothe label and covered with a Petrie dish. The label was tested at periodicintervals to determine whether it could be easily removed. The gel waseasy to apply and keep contained on the label, which helped to ensurethat no tide lines developed in the leather. After five minutes, removal ofthe label was attempted with a spatula, but the adhesive pulled away theupper layer of leather. The gel did not cause any staining of leather butthere was a tide line left on the surface of the label. Ethyl acetate waschosen for a second solvent gel because it seemed to be the solvent thatwas most effective at softening the adhesive. The literature was reviewedbut no published recipe for an ethyl acetate Carbopol 940/Ethomeen C-25gel was found. Several attempts at mixing the gel were made, butwithout success. The gel components separated when the ethyl acetatewas added. Therefore an ethyl acetate gel was not tested on the leather.

DiscussionsOver 20 different techniques were tested for the removal of the labels fromthe leather covers of the books. Most of the techniques did not help toremove the label from the object completely, but a few were moderatelysuccessful. Experimenting with each technique added to the authors’understanding of the labels and the leather.

The two most successful techniques involved a combination of a poulticeand mechanical introduction of the solvent to the underside and edges ofthe label. These techniques resulted in the removal of the label with theleast amount of damage to the leather.

The first moderately successful option was the poultice of cellulosepowder in ethyl acetate placed on top of the label, whilst a brush containingethyl acetate was run along the sides or at the interface between the labeland the leather (Fig. 7). The label could be slowly lifted from the surface

Fig. 7 A label during removal with a cellulose fibre/ethyl acetate poultice and blotter paper‘spatula’ or brush.

42 Stavroudis, ‘Carbopol 934′.



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with tweezers whilst the brush was continually run along the join. Oneadvantage of this technique is that the label could theoretically beremoved in one piece, although in the tests this was difficult to accomplish.A disadvantage of this technique is that it required the use of moderatelylarge amounts of solvent, and could result in tide lines. The tide linescould be reduced by placing blotter paper over areas to absorb excesssolvent. This process required approximately one hour for each label(Fig. 8).

The best overall results came from first thinning the paper layer with ascalpel, then covering it with a poultice and introducing solvent from theside to remove the remaining label. Thinning the paper layer with ascalpel enabled the solvent to penetrate more effectively and reach theadhesive. This technique successfully removed the label from the bookwith minimum damage to the upper layer of the leather but with slightdarkening. Approaching the label removal as a two-step process in whichthe carrier and the adhesive were removed separately was one of themore successful options. This process can take one to one and a halfhours to complete for each label.

ConclusionsLabels specified for permanence can require removal from collection itemsas policies change. This study of label removal techniques for leather booksincluded an evaluation of a variety of different methods. The removal oflabels from historic leather bookbindings is particularly difficult due tothe fragility of the leather and the inaccessibility of the adhesive.However, the techniques discussed in this report can be used as initialguidelines for the development of other methods. The final successfulmethods identified in this article are specific to these books and may notbe the best technique in other circumstances with different labels. Aslibrary policies continue to change and books continue to be transferredto different collections within the library system, the development of effi-cient, safe and successful ways of removing labels from deterioratedleather bindings will continue to be an important area of research.

Fig. 8 Label removal using a cellulose fibre/ethyl acetate poultice and blotter paper ‘spatula’ orbrush. (a) Before treatment. (b) After treatment.



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The goal of the project was to find a technique that could be undertaken bythe library’s technicians, using non-hazardous materials and not causingdamage to the leather. The two most successful techniques tested on thelabels involved a combination of a poultice and mechanical introduction ofthe solvent to the underside and edges of the label. The deteriorated leather’sfragility, especially when combined with the adhesive’s tack, required a tech-nique gentle enough for the leather while still capable of removing theadhesive. Reducing the paper carrier with a scalpel minimized the mechan-ical strain experienced by the grain layer while also exposing the adhesivelayer to the action of solvents. Both techniques with the most promiserequired high levels of dexterity and manual skills, which could be achievedby non-conservators, given training and practice.

Unfortunately, the technique that worked the best required extensive useof solvents, which is not recommended in a non-laboratory setting withoutfume hoods. The authors found it best to use both a fume extraction hoodand a respirator when completing the treatments. Additionally, even therecommended technique occasionally caused areas of tide lines and dar-kening to the leather. Further experimentation with methods to create anethyl acetate solvent gel is recommended as a way to reduce solvent use.Finally, given the nature of these labels, removing them in one piece isnot a realistic goal and would be extremely difficult. The discussion ofthe methods used in this case study reveals the difficulty of removinglabels from deteriorated leather and hopefully will provide a foundationfor future work in this area.

Acknowledgements

This paper would not have been possible without the hard work andinitial tests completed by the following conservators who worked onremoving the labels: Suzanne Morris, Linda Lin, Lauren Horelick,Siska Genbrugge and Jiafang Liang. We give them our mostsincere appreciation. A special acknowledgement is due to KristenSt. John for supporting this project and the UCLA Library forloaning the books to the UCLA/Getty programme for this research.In addition, we thank Vanessa Muros for the FTIR analysis of theadhesive and the many experts and colleagues who providedencouragement and advice, including Tessa de Alarcon, LilyDoan, Elizabeth Drolet, Nicole Ledoux, Dawn Lohnas, Cindy LeeScott, Elissa O’Loughlin, and Amy Crist.

Abstract

This research on label removal from leather was inspired by a real-life circumstance in a library where similar pressure-sensitive labelshad been applied to the covers of a series of eighteenth-centuryleather-bound books. The challenge was to develop a protocol forsafely removing the unwanted labels that could be carried out bynon-specialists outside of a laboratory without causing damage tothe historic bindings. The adhesive was analysed with Fourier trans-form infrared spectroscopy and solubility tests. The degradedsheepskin was characterized by its follicle pattern, shrinkage temp-erature, spot tests and surface pH. A selection of mechanical andsolvent-based techniques was evaluated, including removal with ascalpel, solvent gels, solvent poultices, solvent chambers andchanges in temperature. The best results occurred when the paperlabel was thinned, followed by a cellulose fibre poultice with ethylacetate applied to the thinned backing.

Resume

«Le retrait des etiquettes sur des reliures deteriorees en cuir»Cette recherche portant sur le retrait des etiquettes presentes sur

les cuirs fut inspiree par une circonstance de la vie reelle a la bib-liotheque ou des etiquettes auto-adhesives similaires avaient ete

appliquees sur les couvrures d’une serie de livres relies en cuirdatant du 8eme siecle. Le defi etait de developper un protocolepour retirer sans dommage les etiquettes indesirables, pouvantetre mis en œuvre par des non specialistes, en dehors de l’atelier,sans causer d’alteration aux reliures anciennes. L’adhesif a eteanalyse a l’aide de la Spectroscopie a Transformee de Fourier et al’aide de tests de solubilite. Le cuir de mouton degrade a ete carac-terise par la forme de ses follicules, sa temperature de retrecisse-ment, des tests locaux et le pH de surface. Une selection detechniques mecaniques ou a base de solvants a ete evaluee, allantdu retrait avec un scalpel jusqu’aux gels, cataplasmes et chambresde solvants en faisant varier la temperature. Les meilleurs resultatsont ete obtenus quand le papier de l’etiquette etait aminci puisrecouvert d’un cataplasme compose de fibres de cellulose et d’e-thylacetate.

Zusammenfassung

,,Etikettenabnahme von geschadigten Ledereinbanden”Die Recherche zur Abnahme von Etiketten an ledergebundenenBuchern wurde durch eine reelle Erfahrung in einer Bibliothekinspiriert, wo ahnliche Selbstklebebander auf die Einbande einerSerie ledergebundener Bande des 18ten Jahrhunderts geklebtworden waren. Die Herausforderung lag in der Entwicklung einerMethode, die die sichere Abnahme der ungewollten Etikettenauch Nicht-Fachleuten in normaler Umgebung ohne die Leder-bande weiter zu schadigen ermoglichen konnte. Das Klebemittelwurde mit Fouriertransforminfrarotspektroskopie und mit Loset-ests analysiert. Die beschadigte Schafshaut wurde durch ihr Folli-kelmuster, Schrumpftemperatur, chemische Tests und durch denOberflachen pH Wert charakterisiert. Eine Auswahl mechanischerMethoden und welchen, die mit Losungmitteln arbeiteten wurdengetestet. Dazu gehorten der Einsatz eines Skalpells, verschiedenerLosungsmittelgels, Losungsmittelkompressen, Feuchtkammernmit Losungsmitteln und der Einsatz verschiedener Temperaturen.Die besten Resultate wurden erzielt, wenn das Papier des Etiketts



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erst ausgedunnt wurde und dann das zuruckgebliebene dunnePapier mit einer Cellulosefaserkompresse mit Ethylacetat bestrichenwurde.

Resumen

“Remocion de etiquetas de libros deteriorados encuadernados enpiel”

Esta investigacion sobre la eliminacion de etiquetas sobre piel fueinspirada por una circunstancia real en una biblioteca donde unasetiquetas autoadhesivas se habıan aplicado sobre las tapas de unaserie de libros encuadernados en piel del siglo XVIII. El reto fuedesarrollar un protocolo para que los no especialistas, fuera de unlaboratorio, pudieran remover las etiquetas no deseadas sin causardanos a las encuadernaciones historicas. El adhesivo se analizocon Espectroscopia Infrarroja de Transformada de Fourier ypruebas de solubilidad. La piel de oveja degradada se identificopor su modelo folıculo piloso, su contraccion por temperatura, porpruebas de contacto y por el pH. Una seleccion de tecnicas mecani-cas y a base de solventes fueron evaluadas incluyendo la remocioncon bisturı, con gel y emplastos con solventes, camaras con solventesy cambios en la temperatura. Los mejores resultados se obtuvieroncuando el papel de la etiqueta quedo ralo, seguido por un emplasto

de fibra de celulosa con acetato de etilo aplicado a la superficiedelgada.

Biographies

Robin O’Hern is currently an Andrew W. Mellon Fellow at theNational Museum of the American Indian. She graduated fromthe UCLA/Getty Master’s Programme in Archaeological and Eth-nographic Conservation. She has interned at the Agora Excavationsof the American School for Classical Studies at Athens, the Ameri-can Museum of Natural History, the Pitt Rivers Museum atOxford University, and the Corning Museum of Glass. She receiveda Masters in Theological Studies from Harvard Divinity Schoolwhere she studied religion and material culture.

Ellen Pearlstein is Associate Professor in the UCLA/Getty Master’sProgramme in Archaeological and Ethnographic Conservation and inInformation Studies. She has an MA in art history and archaeologyfrom Columbia University and an Advanced Certificate in conservationfrom the Conservation Center of the Institute of Fine Arts, New YorkUniversity specializing in archaeological and ethnographic objects. Shewas Senior Objects Conservator at the Brooklyn Museum from 1983to 2005 and Adjunct Professor at the Conservation Center from 1991to 2005. Ellen is a Fellow of the American Institute for Conservation.

Materials and suppliers

Attapulgite (58903)Kremer pigments Inc.228 Elizabeth StreetNew York, NY 10012USA

Carbopol 940Nuveen, Inc./The Lubrizol Corporation29400 Lakeland BoulevardWickliffe, Ohio 44092USA

Cellulose powder (cellulose fibres) (F-11)WhatmanSpringfield MillJames Whatman WayMaidstoneKent ME14 2LEUK

Ethomeen C-25 (TCD024001)Talas330 Morgan AveBrooklyn, NY 11211USA

ACS Ethyl Acetate (EX0240-6)EMD Chemicals480 S. Democrat Rd.GibbstownNJ 08027USA

Ferric sulphate (S93243)Fisher science education15 Jet View DriveRochester, NY14624USA

Laponite RD (MS16)Conservation Resources (UK) Ltd15 Blacklands WayAbingdon-on-ThamesOxon OX14 1DYUK

Methyl cellulose (TAD016004)Talas330 Morgan AveBrooklyn, NY 11211USA

PVA spongeSaugwunder Polyvinyl Alcohol Sponge(TCD107001)Talas330 Morgan AveBrooklyn, NY 11211USA

Vanillin, Reagent plus 99% (H0264)TCI America9211 North Harborgate StreetPortlandOR 97203USA

Contact addresses

Robin O’HernNational Museum of the American IndianCultural Resources Center4220 Silver Hill RoadSuitlandMD 20746USAEmail: [email protected]

Ellen PearlsteinUCLAA210 Fowler BuildingLos AngelesCA 90095-1510USAEmail: [email protected]



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Documents

Label removal from deteriorated leather-bound books