- ts s paper F el R W EVIE R RE TU ERA Why are these solutions drawing out more discolouration and Why are these solutions drawing out more discolouration staining? Are they safe to use on paper and media? T ellowing in paper In order to approach these questions it was necessary to review establish what is the mechanisms of yellowing in paper and to level when paper being removed at an elemental and molecular would inform is washed. It was anticipated that this information is being accessed the question: what part of the discolouration it reach? Similarly, by the three solutions that water alone cannot on ammonia, was hoped that a review of the available literature and would contribute towards answers to these and TAC EDTA should be questions, offer recommendations for how they by used, and identify problems that have been encountered conservatorswith their usage. of preliminaryThe final part of this paper presents the results was carried out to examine elementally which testing using XRF, the three the changes to a series of papers treated with substances examined. These observations initiated two lines of inquiry: 1. 2. This paper presents the preliminary investigations into answering these two questions. groups contain double bonds which cause a yellow appearance presence The oxidation reaction can be catalysed by the in paper. of metals in the paper especially copper and iron. Such reactive metals can bond with lignin to cause highly coloured compounds (Hart 1981, p.43). Metal ions may find their way into paper during manufacture in the water used or from the breakdown of processing equipment. fibres can also contain trace metals from the soil. All papers Wood metals as well as other trace are said to contain iron and copper, depending on the location and period of their manufacture (Hey 1979, p.77). Lignin on its own is a source of discolouration LI Y Discolouration of paper is a natural consequence of oxidation on aging. Through acid and alkali-catalysed degradation chromophores are formed which absorb blue/violet light (Daniels 1996, p.181). Daniels states that discolouration products can be obtained from any of the ingredients that make up paper and the range of chromophores that can be expected is correspondingly large. cellulose, forms chromophores The major component of paper, when it undergoes oxidation as hydroxyl groups are converted first to carbonyl and finally carboxyl groups. Carbonyl and carboxyl elzer M N IO CT DS RA DUCT OR RO YW revealed that a deionised water rinse after the use of either of the chelating agents allowed calcium to be redeposited in the agents allowed calcium to be redeposited water rinse after the use of either of the chelating revealed that a deionised wash. in a subsequent buffered ABST additives that were observedThis paper explores three removal of discolouration from paper during to generally enhance the and triammonium citrate (TAC); tetra acetic acid (EDTA) included two chelating agents; ethylene diamine washing. The additives as the potential for the enhanced washing as well The investigation explores the possible mechanisms and ammonia solution. A literature review and preliminary with X-ray florescence (XRF) testing might have on paper. impacts that these solutions chelating agen points. The XRF analysis identified that the two in order to begin addressing these spectroscopy were undertaken Further analysi of calcium during a buffered wash. quantities of calcium and inhibiting the re-uptake were removing significant E NT provide greater stain reduction or enhance the extraction of overall discolouration in paper than occurred with deionised or calcium- buffered water alone. The significance of these observations is and in the case of the chelating that they occurred consistently, agents, they occurred with discolouration not traditionally associated with metal ions – the primary area of chemical interaction of these two reagents. be difficult to control and can have adverse affects on the paper through further oxidative degradation or the evolution of gas bubbles. Recently at the Centre for Cultural Materials Conservation(CCMC), paper conservation has been exploring a number of alternative washing aids: ammonia solution and two chelating agents: TAC These have been observed circumstances to in some and EDTA. alkaline buffers to solubilise and extract more acidic products. It is often the case that these solutions stop being effective before the yellowing and staining have been sufficiently reduced to be considered not disfiguring. If it is deemed necessary to continue reducing staining or discolouration, for example if the work must function as an aesthetic object, then the conservatorresort may to bleaching. While bleaching can be veryalso effective, it can (XRF), and the possible chemical pathways for the process of (XRF), and the possible chemical pathways for analysis suggest their actions are explored. The results of this and by EDTA that significant quantities of calcium are removed to the increased solubilisation of and this may be contributing TAC discolouration. purified water has been used to extract discolouration Traditionally and with aids such as ethanol to improve wetting from paper, additives to the washing process that have been observedadditives to the washing process that have been to than had have a wider effect on the removal of discolouration been previously noted. It explores the chemistry of paper treated triammonium citrate with ethylenediamine tetra acetic acid (EDTA), of determining what substances and ammonia with the aim (TAC) efficacy of attempts are removed, what residues are left, and the The elemental surface to replace potentially lost buffering material. chemistry with x-ray fluorescence spectroscopy is examined I a long tradition material has Aqueous treatment of paper-based in paper conservation. The use of water with various additives to has been extensively remove soluble acidic material and impurities explored in the conservation literature. This paper outlines a preliminary into the chemical interaction of three investigation K ammonia, washing, XRF TAC, EDTA, paper, A preliminary investigation into three aids to washing paper: X paper: washing aids to three into investigation A preliminary and ammonia TAC with EDTA, of paper treated analysis emental Libby Pemberton and Briony
2010 AICCM BOOK, PAPER AND PHOTOGRAPHIC MATERIALS SYMPOSIUM 58 2010 AICCM BOOK, PAPER AND PHOTOGRAPHIC MATERIALS SYMPOSIUM 59 into the chemistrythat of urine and urea as they age indicated solubility decreased coinciding with the off-gassing of ammonia. Preliminary testing involved reintroducing ammonia in an attempt with ammonia to revert the urea to a soluble state. Treatment increased the solubility of the stains, though no testing has been carried out to see if the effect is the result of the original hypothesis or a by product of the general increase in cleaning observed with ammonia solutions. Chelating agents A chelating agent is a negatively charged compound capable of forming a strong ring structure that incorporates a metal ion. structures, which suggests they had become soluble due to the structures, which suggests they had become chemical environment in the stained area’. other cleaning One of the perceived benefits of ammonia over it would not leave agents, is its volatile nature which suggests that Research by Koura and Krause indicated residues in the paper. for the elimination of that evaporation is the most efficient method ammonia from paper (1987, p32). that ammonia Anders, Bredereck and Heberditzl (1996) state is not suitable for use in paper conservation since it causes for this assertion shrinkage of between 10 and 20%, but the basis of 5% for is not clarified. Feindt notes an average shrinkage with higher samples treated in pure ammonia and 85% ammonia to hand-made shrinkage for machine-made paper compared are at pH 9, which papers. Ammonia solutions used at CCMC is less than 0.05% vol/vol. They have been used locally and generally and no evidence of shrinkage has been observed. Ammonia has the potential to interfere with pH sensitive media and some mention has been made of the possibility of alkaline solutions to saponify oil based inks including some printing inks (Book and Paper Group 1990, p.18). Experimentation with ammonia at CCMC began as a result of two projects. The first involved testing the viability of treating a series of badly mould stained but physically intact works on paper. A solution of ammonia at pH 9.5 was tested in an attempt to increase solubility by altering pH, and proved the most successful of all washing treatments tested. The second treatment involved a series of works badly stained by aged cat urine. Research Ammonia conservation of ammonia to the The application treatment of paper the focus to have not been adaptation, but seems is not a recent Keiko Keyes In the 1980’s in recent years. of much attention Koura & to bleaching paper and it as a safe alternative suggested in liquid of ammonia identified high concentrations Krause (1987) paper. treatment of embrittled phases for the mass and gaseous is its ability to break the cross-links The useful action of ammonia in the crystallinebetween cellulose molecules regions of highly then appear to be re-established as hydrolysed papers, which increasing fold strength and flexibility. amorphous areas, thereby of ammonia permits it to break hydrogen The highly basic nature molecules which are not accessible to bonds between cellulose in textile conservation This action is well established and water. is an alternative to sodium hydroxide manufacture where ammonia cotton (Rouette 2001). for the mercerisation of ammonia as being suitable for use Keiko Keyes (1987) identified in solutions of up to 0.05% and indicated in the washing of paper than solutions that it yielded a brighter paper after washing The of either calcium hydroxide or magnesium bicarbonate. the discolouration mechanism for the increase in solubilisation of that increasing the is not addressed, but it could be extrapolated to which they had accessibility of washing to regions of the paper quantity soluble previously been excluded would allow a greater of foxing would (1996) analysis material to be accessed. Florian’s would work on give a potential explanation as to why ammonia alkaline [she used this type of stain, because she found that ‘an fungal sodium hydroxide] solution dissolved all the protein-stained Washing in water alone will not remove carboxylic acid groups Washing from the cellulose molecules or partially hydrolysed aluminium an if these acid groups are neutralised with sulphate. However, alkaline material such as calcium hydroxide, they can be made more soluble and more able to be extracted (Hey 1979 p.70; Burgess 1988, p.15). This implies that a portion of the degraded cellulose and the alum sizing agent are being washed out during aqueous treatment with calcium-buffered water. soluble component of paper discolouration is simply broken down cellulose and other components. The monosaccharides detected included mostly arabinose, xylose, rhamnose and galactose, with smaller components of glucose and mannose. This supports statement that ‘the majority of the soluble Haverman and Dafour’s fraction of degradation products is composed of neutral sugars’ (1997, p.107). the types of soluble acidity (Hey 1979, p.66). Other substances washed out are short chain cellulose degradation products. An analysis of ‘paper extract’ (a substance used for paper toning obtained by extracting and reducing the highly-coloured water- soluble material from old degraded mount and back boards) showed it was composed of monosaccharides - the most basic units of carbohydrates (Ormsby 2001). This suggests that the reducing staining and discolouration when EDTA did not, and vice reducing staining and discolouration when EDTA versa. paper Washing According to the literature, the coloured substances that are removed during washing are the products of paper degradation of Sulphuric acid is mentioned as one such as soluble acidity. to the wider application of EDTA, first to more wide-ranging stains to the wider application of EDTA, discolouration. including mount burn, and finally to reduce general Nola Orr (2007), Previous research by CCMC Masters student triammonium citrate suggested that an alternative chelating agent, citrate Triammonium on paper. may also be safely used (TAC) is used widely by painting and objects conservators. Earlier ad may prove affective at hoc experiments had suggested that TAC The reported presence of iron in foxing is what prompted The reported presence of iron in foxing is what given its conservatorsat CCMC to start exploring the use of EDTA removal from paper. ability to chelate metals and thus facilitate their to reduce of EDTA It was during these treatments that the property was general discolouration in paper was observed. When EDTA wash, over- applied locally to a foxing spot during a general observed.cleaning around the staining was sometimes This led of both. There is general agreement that the sites of foxing spots of both. There is general agreement that the surrounding paper have a greater degree of oxidation than in the is chemically (Bicchieri et al 2001). The foxing spot itself therefore, overall oxidation not unlike a sheet of paper that has suffered then paper, as a result of natural ageing. So if foxing is oxidised as described presumably the same reactions have occurred above. degradation products’ and include furfural, which is formed degradation products’ residues in the hemicelluloses and from the pentose sugar which is formed from the glucose units 5-(hydroxymethyl) furfural, & Bredereck1996, p.482). of the cellulose (Anders Foxing form of discolouration, the cited Foxing in paper is a specific fungi, metal particles or a combination causes of which include sulphur and these can also contribute to colour production to colour production these can also contribute sulphur and p.93). (Daniels 1988, expected in paper include furans, The types of chromophores stilbenes, with furans evidently quinones, methides and discolouration (Hon 1979; Lewin 1965). producing most of the as ‘volatile non-acidic organic Furan derivatives are described as described in a paper by Hon: ‘The phenolic groups in lignin in lignin groups ‘The phenolic paper by Hon: in a as described with its oxidation to coloured associated closely molecules are In addition to these (Hon 1981, p.130). quinonoid products’ be formed organic acids may metal/lignin reactions, oxidation and and the uptake of nitrogen during ageing through in the paper The . A book was chosen 3 printed on a highly lignified paper D O TH Deionised water Saturated calcium hydroxide in deionised water applied drop- wise to pH 8 Ammonia in deionised water applied drop-wise to pH 9.5 0.1M with NaOH to pH 8.5 in deionised water EDTA 5% wt/vol in deionised water TAC E
The paper chosen for testing was a 1963 copy of the book The paper chosen for testing was a 1963 copy !"#$%&'()*+,&'-*.&/+01+!$-**#2* that is likely to contain alum rosin size M page re-washed with deionised water and the calcium hydroxide solution. The pages selected for formal testing were adjacent pages which were taken from the centre of the book to reduce the likelihood of disproportionate soiling from handling or deposition. Samples 1. All samples were pre-wet were prepared as outlined in Table with ethanol applied with a dahlia sprayer and air dried after treatment. for testing so as to allow a large number of samples of relatively for testing so as to allow a large number of samples the same natural uniform composition, which had undergone had been stored for aging process. It was known that this book artificial heating most of its life in a subtropical environment, without or cooling and in close proximity to the beach. A preliminary cycle was carried out to confirm the testing observation solutions were drawing out additional that immersion washed discolouration. This involved five pages being pages The minutes. 30 of cycles two for bath water deionised a in The test pages were were then transferred to wet blotting paper. and individual brushed into close contact with the blotting paper, sheets were brushed out with the following solutions: 1. 2. 3. 4. 5. Further mobilisation of discolouration was able to be observed of these Results as transferred impression on the blotting paper. preliminary tests showed additional discolouration was solubilised by the three test solutions, with minimal further movement from the can achieve a neutral pH (of 7) at 5% solution concentration. It is concentration. 7) at 5% solution pH (of a neutral can achieve surface conservatorsremove painting to by 1-5% used between at ability to remove for TAC’s paintings. The mechanism grime from of organic and inorganic generally a combination dirt, which is recent theorynot fully understood. A material, is is that calcium dust, accumulation of building in the dirt from the ions are present it also solubilises the these metals, chelates TAC so when the pers. comm., 15 Februaryattached dirt (C Stavroundis, 2010). does not have a documented history citrate of Triammonium use in paper conservation,part prompted CCMC which in Orr to investigate its potential. In Orr’s Masters student Nola different at three were treated with TAC study (2007), four papers & 5%, all solutions showing a pH of just concentrations; 1%, 2% pre-wet with ethanol and deionised under 7. All papers were then solution for 20 mins, in the TAC water (50/50), immersed water for 20 mins each time. Papers rinsed twice in deionised pH and after ageing using colourimetry, were analysed before Results showed that in terms of testing and tensile testing. use of triammonium citrate the stability, strength, colour and pH the papers tested. did not produce any detrimental changes in that calcium and There was an indication from the pH testing of the papers and it magnesium were lost during treatment of one be countered by was acknowledged by the author that this might wash. Microscope following the treatment with an alkaline-buffered analysis indicated that no crystalline material was left on the surface of the papers after treatment.
1 , and 2 aqueous solution depending on cations present, and complexes aqueous solution depending on cations present, states as well as nearly all metal ions in their full range of oxidation which exist only in alkali earth metals like magnesium and calcium and Paper Group one oxidation state (Burgess 1991 p.39; Book stains such as rust, 1990, p.18). In addition to its use for metallic metals in paper it is also suggested as a way to remove transition borohydride before bleaching with hydrogen peroxide or sodium stains in paper and to enhance the removal of oily or greasy EDTA (ethylenediamine tetra acetic acid) (ethylenediamine EDTA agent to paper conservatorsThe most familiar chelating is treatment to its recommended use as a rust-removal due EDTA, the salts of (Suryawanshi 1991). EDTA, & Bisaria 2005; Burgess acid, has been commercially available ethylenediamine tetra acetic It may be in an acidic or alkaline form in since the mid-1930s. in solution. It is therefore often recommended to first use a to first use It is therefore often recommended in solution. ferric coloured, insoluble for example to reduce reducing agent, colourless, ferrous form (II). iron (III) to the more water-soluble, will be in ferric form. Any ferrous iron Most iron stains in paper by simple water washing, although would probably be removed speed up the process and potentially a chelating agent would prevent redeposition. This caged ring structure alters the reactivity of the metal ion of the the reactivity alters ring structure This caged p.43). a reaction (Hart 1981, it from entering into and prevents in conservationchelating agents are used this ability, Because of the dirt. They work best when staining or to reduce metal-based chelated are both present and the metal to be chelating agent dangers of EDTA are the presence of high concentrations of are the presence dangers of EDTA and calcium from sodium ions and the removal of magnesium work should therefore be washed extensively The the paper. sodium in water after treatment to flush out the excess (Burgess 1991, p.42). No article was found that mentioned the (Burgess 1991, p.42). No article was found that of overall yellowing in paper. for the reduction use of EDTA the recommendation is to make safely on paper, use EDTA To that is adjusted to a pH of 7 to 8 solution up a 0.1 molar EDTA is grams of EDTA achieve this, 32.7 (Burgess 1991, p.40). To with the addition of 5-10% dissolved in 1 litre of deionised water, The potential sodium hydroxide until desired pH is reached. Triammonium Citrate, the salts of citric acid, is commercially Triammonium It is soluble in water and available as a white crystalline powder. sodium dithionite (Suryawanshi study & Bisaria, 2005, p.284). The alone is too damaging to the paper and concluded that EDTA that it should be used with alkalis to protect the physical strength stains, In terms of removing iron properties of the treated paper. was it was found that sodium dithionite in combination with EDTA the most effective. citrate) (Triammonium TAC papers. It is accepted however that EDTA needs to be used very papers. It is accepted however that EDTA it is cautiously on media. In addition to the findings of this study, among other chelating agents, has been used known that EDTA, in the paper recycling industry ink to aid in the removal of ink and binders (Hart 1981, p.44). Another study looked at iron stain removal using different alone, with buffering agents, and with concentrations of EDTA, treated with 1% EDTA tended to yellow on storage and colour treated with 1% EDTA change occurred with a number of pigments (Norville-Dayet al 1997, pp.142-148). While these results are not encouraging, the solution does not appear to have been buffered to improve EDTA its working pH, and the amount of washing time after treatment to remove damaging sodium ions was not mentioned. Furthermore, there was no mention of replacing lost calcium and magnesium. All of these factors could have contributed to the yellowing of the enough calcium or magnesium should be returned to the paper to enough calcium or magnesium should be returned pp.40-41). Part of replenish what has been lost (Burgess 1991, was to determine the experimental process of this research project the latter. the quantities of calcium required to achieve and pigment stability have been on paper The effects of EDTA papers One study found that a selection of examined previously.
2010 AICCM BOOK, PAPER AND PHOTOGRAPHIC MATERIALS SYMPOSIUM 60 2010 AICCM BOOK, PAPER AND PHOTOGRAPHIC MATERIALS SYMPOSIUM 61 N IO SCUSS was able to be extracted from the sheets with the addition of EDTA was able to be extracted from the sheets with the addition of EDTA Since only minor quantities of iron were removed with and TAC. chelating agents, these results suggest that when chelating agents of this is not related to the extraction reduce yellowing in paper, iron. The failure of calcium to be readsorbed by the paper when a chelating solution is followed by a calcium hydroxide buffered wash suggests that residues of the chelating solution remain in the paper and are preventing the calcium being deposited. The cleansing action of the pure deionised water rinse appeared sufficient to reduce residues and allow calcium levels to be with ammonia solutions reduced the replenished. Washing calcium in similar fashion to deionised water alone, but did not DI contributing to oxidative Iron has a destabilising effect on paper, impact on the degradation. Any removal of iron has a positive the reduction of iron In this way, stability and longevity of paper. The failure found with most washing techniques was encouraging. in comparison to of the chelating agents to further reduce iron that fact that they buffered washing alone may be explained by suggested Two are simply not able to access the residual iron. in an insoluble mechanisms for this trend are: if the iron exists into solution thus state (FeIII) then it may not have been pulled if the iron is bound in an preventing the chelation; alternatively, the chelation inaccessible part of the cellulose macro-molecule, similarly could not occur. In the first instance, chelation may be enhanced by reducing the iron to its soluble state (FeII). Sodium dithionite has been mentioned in the literature for this express purpose. In the second instance the addition of ammonia as precursor or addition to the chelating solution may increase the amorphous regions of the paper and permit the chelation of previously inaccessible iron. Both these hypotheses present areas for further research. The failure of pure deionised water to remove as much iron as the buffered solutions may result from a lack of available ions in the wash solution for ion exchange. As demonstrated by the first stage of testing, further discolouration Hey, calcium levels were significantly higher than pre-treatment calcium Hey, levels (Hey 1979 p.74). reduced with all other washing methods though not significantly. significantly. though not methods washing with all other reduced any effect did not appear to have of a buffered wash The inclusion levels. on the potassium levels of iron were reduced showed that significant The results and TAC Suprisingly EDTA by all washing techniques. consistently calcium with ammonia and more iron than washing removed no chelate theoretically and TAC since EDTA This is interesting water. all oxidation states. All solutions removed metals including iron, in water alone. more iron than deionised with regard to the effect of the Clear trends were presented on calcium present in the samples. various washing treatments with the exception of the calcium All of the washing processes, removed measurable quantities hydroxide buffered solution, of calcium was removed by the of calcium. The least amount ammonia solutions. The greatest deionised water and pure by the two chelating agents. Not amount was removed in the calcium content of the there was in increase surprisingly, hydroxide buffered water wash. paper after the calcium a calcium hydroxide When the ammonia solution was followed by levels equivalent or buffered wash, the uptake of calcium was to the chelating agents slightly higher than before treatment. When wash there was were followed by a calcium hydroxide buffered agents were no measurable uptake of calcium. If the chelating hydroxide followed by a deionised water wash, then a calcium to pre-treatment. wash, calcium uptake reached levels equivalent increased to 50% If the calcium level in final buffered wash was by Margaret saturated calcium hydroxide solution as described
O: sat. O: sat. 2 2 O/CaOH pH O/CaOH pH 2 2 H H 1:1 H 1:1 H CaOH pH 10 x 30 min CaOH pH 10 x 30 min 8.5 x 30 min 8.5 x 30 min RINSE/ BUFFER O x 30 O x 30 O x 30 O x 30 2 2 2 2 O/CaOH O/CaOH O/CaOH 2 2 2 DIH DIH H min min min min RINSE/ BUFFER min pH 8.5 x 30 min pH 8.5 x 30 min pH 8.5 x 30 DIH DIH H H + + + +
,-.# ,-.# ,-.# ,-.# + + + + O/TAC 5% '(&)*" '(&)*" O/TAC 5% O/NH3 pH 9.5 O/NH3 pH 9.5 '(&)*" '(&)*" O/TAC 5% x O/TAC 5% x 2 2 2 2 2 2 2 2 2 2 x 30 min x 30 min x 30 min x 30 min WASHING AID x 30 min x 30 min x 30 min x 30 min 30 min 30 min H H H H H H H H H H . 5 O 30 min x2 O 30 min x2 O 30 min x3 O 30 min x2 O 30 min x2 O 30 min x2 O 30 min x2 O 30 min x2 O 30 min x2 O 30 min x 2 O 30 min x2 2 2 2 2 2 2 2 2 2 2 2 O/CaOH pH 8.5 2 DI H DI H DI H DI H Control DI H DI H DI H DI H PREWASH DI H DI H x 30 min x 2 DI H H . Proprietary AXS software was used for semi- Bruker 4 SULTS E 7 13 11 12 !"#$%& 1 2 10 8 6 9 4 5 3 quantitative comparison were tested per sheet. These were taken from from each page at were tested per sheet. These were taken from consistency for the fore-edge, the gutter and the centre to allow comparison between samples. Small samples were cut from test pages avoiding ink where Small samples were cut from test pages avoiding Three locations possible and placed on the sensor of the XRF. with deionised water or the ammonia solution. It was consistently analysis showed a significant reduction through all washing treatments tested. The remaining elements presented recognisable trends. Potassium is potentially present as part of a potassium aluminium sulphate size, and is perhaps the least significant of the identified It presented elements in regard to the permanence of paper. inconsistent results, or appeared to be unaffected by washing were not further considered within this project. Chlorine was affected uniformly by all treatments, being largely salts from removed. Its presence may be the result of the air-born close proximity to the beach or as residues from a the book’s manufacturing process. Chlorides are potentially harmful to paper through the formation of hydrochloric acid and encouragingly magnesium. These were considered individually with regard to their potential impact on the paper chemistry and their comparative behaviour between samples. Silicon and aluminium appeared unaffected by all the washing treatments tested. Their presence may be indicative of fillers or sizes. They were not considered further in this research. Magnesium peaks were too small for meaningful comparison so R Spectra obtained indicated peaks for the following elements: silicon, aluminium, chlorine, potassium, calcium, iron, and Testing was carried out on test pages with Brucker Tracer III-V Brucker Tracer was carried out on test pages with Testing of Museum handheld X-ray fluorescence analyser courtesy Victoria Table 1. The !"'A#2-$+ . by J.C. Paper , Vol 57, no.7, pp. , Vol Preservation of Preservation , vol II London, pp 481- , 15, pp.36-44 , Butterworth, London, pp. 37-41 , 7th edition , 41, pp. 65-75 3!45+!0(1'&'(2'+6-7'&*8+99:"+,&#'((#-$+ !0(*'&F-:#0(+01+H#=&-&/+-(%+C&2"#F'+ , 12, pp. 93-100 S , 25, pp. 179-186 E @7'2:&02"#A#2-+C2-:+6-&:+D S E The Paper Conservator NC T O ERE F E Kaiser for the testing of paper: blue filter, 15KeV, 15µamp, 180 15KeV, Kaiser for the testing of paper: blue filter, sec assay EDTA may work on these stains because they will be present as work on these stains because they will be may EDTA iron, or copper fatty acid salts of calcium, which is why they acidity in paper, Sodium residues can produce 1979, p.77). after treatment (Hey, need to be flushed out using The highly lignified nature of the paper was determined positive result. phloroglucinol spot test which gave a strong The Iodine-potassium iodide test for starch was negative. the inexpensive and suggestion of an alum rosin size is based on the absence of a starch sizing, functional nature of the paper, as detected using and the presence of potassium and aluminium XRF Dr Bruce Setting were as recommended by Bruker Consultant Bruker XRF Handheld Inc. S1PXRF version 3.8.24
Feindt, W 1987, ‘Increase of paper permanence by treatment with liquid ammonia or ammonia solutions: Part 2, The influence of treatment with liquid ammonia or ammonia solutions on the permanence of inks’ 5-:'&#-$*+-(%+:"'+I&-7"#2+C&:* Florian, M 1996, ‘The role of the conidia of fungi in fox spots’, Studies in Conservation Elements in Paper Hanson, V 1981, ‘Determination of Trace by Energy Dispersive X-Ray Fluorescence’, 6-7'&+-(%+,'J:#$'*+01+K#*:0+-(%+C&:#*:#2+L-$.'+33+'% Williams, Advances in Chemistry Series 193, American Chemical 5 R ‘Mechanisms of Anders, M, Bredereck K and Haberditzl A 1996, Combined with Paper Aging and Non-aqueous Deacidification Paper Strengthening’ 5'':#(;8+<%#(=.&;"+9>?+@'7:'A='&+9BB? 487 for ConservationBook and Paper Group of the American Institute 1990, ‘16.Washing’, of Historic and Artistic Works Conservation Catalogue Burgess, H 1991, ‘The Use of Chelating Agents in Conservation Treatments’, Bicchieri, M et al. 2002, ‘Study of foxing stains on paper micro-X-ray by chemical methods, infrared spectroscopy, fluorescence spectrometry and laser induced breakdown spectroscopy’, 1235-1249 Daniels, V 1988, ‘The Discolouration of Paper on Ageing’, Paper Conservator Chemistry‘The Conservation’,1996, Paper V of Daniels, @02#':/+E'F#'G* ENDN 1 2 3 4 Statistical validity Statistical a preliminary has been designed as The testing process only, target of may become the of identifying trends which with the aim The authors acknowledge more in-depth research. further and to the relevance due are limited in the statistical that the results of leaves tested. The use and variety of samples limited number and of a naturally aged paper, book allowed the use from a single of wide variety of washing scenarios, permitted the comparison a single and highly specific paper type, but limited the results to the subject of intensive washing and one not most frequently treatment.
NS IO
NCLUS Assess physical and chemical properties of papers treated, before and after ageing Evaluation of the viability of buffering EDTA with ammonia Evaluation of the viability of buffering EDTA ability to access to potentially facilitate the chelating agent’s previously un-accessible regions of the cellulose macro- molecule Quantification of residual sodium levels in the paper after treatment Assessment using colorimetry of of changes in the brightness the paper treated with washing solutions of calcium re-buffering solutions. This study indicated that a deionised water rinse after the use of chelating agents significantly improved the uptake of calcium into the paper. and TAC Exploration of the use of lower concentrations of EDTA to prevent residues remaining in the paper As chelating agents remove beneficial calcium from the paper, As chelating agents remove beneficial calcium from the paper, buffering material will need to be replaced
ecommendations 3. 4. 5. Several further potential areas for research have been identified: 1. 2. 1. 2. Residues of chelating agents appear to prevent the uptake further solubilisation of discolouration. Conversely the relationship further solubilisation of discolouration. Conversely is an area of further between calcium and discolouration in paper research. R As a result of this investigation, the authors can make the following recommendations for the safe use of the solutions examined: ageing of paper failed to provide clear explanations for why the ageing of paper failed to provide clear explanations There are in paper. solutions examined improved general washing and of on paper, conflicting studies with regard to their safe use but in the majority particular concern is their interaction with media, safe. and within defined parameters, they are considered This preliminary investigation suggested that iron removed from the factor in the paper during washing did not represent a significant The potential for EDTA to leave harmful sodium residues in the to leave The potential for EDTA able to detect paper remains of concern, however XRF is not part of this study. sodium, so levels could not be assessed as CO In conclusion, a review of conservation and wider literature on the accessible more discoloured components. This is supported by accessible more discoloured components. is that “the Anders, Bredereck and Heberditzl whose assertion new reactive functional groups in oxidised cellulose represent by ionic bonds centres, which can crosslink the cellulose chains such as acetal (with earth alkali cations) and by covalent bonds, and more brittle” and esterbonds, making the fibres less flexible (1996, p.483). significant yellowing was extracted in the first phase of testing significant yellowing was the calcium hydroxide buffered wash, with all solutions except solubilisation of yellowing in paper is the hypothesis that the of calcium has not been disproved, connected to the removal research in this area. For example opening avenues for further agents are breaking cross-linking of it is possible that chelating calcium may be contributing) and making the cellulose (to which concentrated calcium solution. The analysis indicated that analysis indicated calcium solution. The concentrated deposits of calcium hydroxide lower concentrations washing with suggesting that the paper, of calcium within smaller quantities may eventually provide enough of a cycles at lower concentrations residual buffer. of calcium were removed in all washing As significant quantities calcium hydroxide buffered wash, and treatments except the inhibit the uptake of calcium in the same way as the chelating chelating way as the in the same of calcium the uptake inhibit agents did. additional buffering which left significant The only treatments included the highly paper were those that material in the
2010 AICCM BOOK, PAPER AND PHOTOGRAPHIC MATERIALS SYMPOSIUM 62 2010 AICCM BOOK, PAPER AND PHOTOGRAPHIC MATERIALS SYMPOSIUM 63
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graduated from the University of Canberra with a graduated from the University of Canberra with PH WL CT O A NT CO Briony Pemberton Paper Conservator Centre for Cultural Materials Conservation Email: [email protected] Libby Melzer Senior Paper Conservator Centre for Cultural Materials Conservation Email: [email protected] wide variety of clients. Briony also delivers lectures and practical wide variety of clients. Briony also delivers lectures Conservationsessions for the Masters Course in Cultural Material of Arts in Fine at the University of Melbourne. She has a Bachelor Art History History and from the University of Melbourne (1995) and a Masters in Paper Conservation from Camberwell College on the historyof Arts, London (1999). She has presented papers and the treatment of the graphite pencil, pressure-sensitive tape, of an 18th century mezzotint. She has undertaken research into published the findings efflorescence found on leather bindings and an exhibition in the 2008 AICCM Bulletin. In 2001 she co-curated Britain. on drawing materials at Tate Libby Melzer Bachelor of Applied Science in Conservation of Cultural Materials specialising in paper conservation. She was the Ian Potter Art ConservationCentre paper conservation intern in 2002. In 2004 for Ambassadors she completed a seven-month Australian Youth Development Project surveying and developing a management plan for a collection of Spanish colonial Church archives in the provincial centre of Bohol in the Philippines. Libby is Supported by an Australian Postgraduate Award, currently undertaking her Masters by Research into the Materials of French and Flemish Illuminated Manuscripts and Techniques in Australian Collections. She has previously been employed as a Paper Conservator in by the National Archives of Australia Canberra and Melbourne. She is the current treasurer of the Victorian Division of the Australian Institute for the Conservation of Cultural Materials. ACKN XRF analyser kindly lent by Museum Research assisted with Victoria for assistance with the Museum Victoria, Elizabeth McCartney, XRF analysis elemental assay Bruker AXS, for XRF Dr Bruce Kaiser, for Cultural Materials Conservation,Dr Petronella Nel, Centre for useful and informative discussions University of Melbourne, BIOGRA Briony Pemberton Gallery in London, since 2000, undertaking positions at the Tate the and Wales, The State Libraries in Victoria and New South National Gallery of Victoria. She has been at the Centre for Cultural Materials Conservation since 2007 working primarily on on paper for a the consultancy program, where she treats works Ammonia 30% solution Ammonia Pty Ltd Chem-Supply @0%#.A+"/%&0J#%'+7'$$':* Pty Ltd Chem-Supply !-$2#.A+"/%&0J#%' Pty Ltd Chem-Supply
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