The conservation of cultural heritage for sustainable development

Acidic books in . How to count them?

Andrzej BARAŃSKI, Krzysztof FRANKOWICZ, Zbigniew HARNICKI, Zbigniew KOZIŃSKI and Tomasz ŁOJEWSKI*

Summary changes colour, from yellow for pH under 6.5 to The acidity of over 11 thousand books from the years lavender for pH values over 7, and thus is well-suit- 1938–2001 was tested with a pH-pen at the Jagiellon- ed to differentiate acidic paper from that which is ian , Cracow, . A characteristic curve was neutral or alkaline (MCCRADY, 1995). obtained, with a breakthrough in paper acidity in the Since no statistics have been published recently on the years 1994–1996. The total amount of acidic books in acidity of paper produced by Polish manufacturers, the the studied library has stabilised at 1.5 million volumes, first question was whether new books coming to the which makes up 83% of the whole collection. A paral- Jagiellonian Library, or any other library in Poland, were lel survey carried out at two smaller libraries in Cracow acid-free. A sample of 2500 titles was tested from a to- showed a very similar pattern of change in the acidity of tal of 54 thousand new acquisitions for the year 2001, books. On the basis of these findings, the authors pos- only 18 of which were printed on acidic paper. This re- tulate that a statistically significant analysis of the acidity sult shows that even without regulations forcing paper of paper in a library holding the status of a national li- mills in Poland to produce acid-free paper, the era of brary (and thus having every title printed in a given poor quality, unstable paper in Poland has ended. The country) could be used for the estimation of the number acidity test was continued with samples of 1000 titles of acidic books in any other library in the country. from selected years, going back to 1955. For the years 1948 and 1938, the number of tested titles was small- er (300 and 374, respectively). Volumes were chosen Paper has been the main information carrier for 2000 randomly, but only one copy of a given title was taken years. Unfortunately, for almost 150 years it has been for testing. Obtained results are presented in Figure 1. produced by methods which have not allowed it to The percentage of books printed on acidic paper is last. New paper-making technology introduced in 1850 nearly 100% for the years from 1938 to 1985, drops involved formation of paper in an acidic environment. dramatically in the mid-nineties to 3.5% in the year Cellulose in paper produced with this technique is prone to acidic degradation. The mechanical proper- 100 ties of paper deteriorate to the point in which pages of books or documents become brittle and therefore 80 cease to exist. Libraries and archives find themselves 60 in a situation where they are unable to carry out their 40 role in preserving human heritage in its original format.

Percentage of 20 Various methods of mass-scale paper deacidification acidic books [%] are available on the market nowadays. Poland is faced 0 with the problem of organising the deacidification of 19351945195519651975198519952005 its endangered collections. To calculate the scale (and Year cost) of such an operation, an estimate is needed of Figure 1. The percentage of acidic books at the Jagiel- how many books in Poland are acidic and should be lonian Library. deacidified. The survey was carried out at the Jagiellonian Library 1 pH-pens used in this study were produced at the Faculty in Cracow, which is the main library of the Jagiellon- of Chemistry, , in a large number and ian University. With its collection of about 4.7 million were distributed free of charge among librarians, archivists objects, it is the biggest library in southern Poland. and others interested in acidic-paper problems in Poland. At the same time a web page devoted to this topic was The Jagiellonian Library collects at least two copies launched at the Jagiellonian Library web site and its ad- of every printed book, magazine or newspaper in dress was printed on the pH-pen grip, so anyone interest- Poland. The core of the book collection, located at ed could easily find not only instructions on how to use the the main building (apart from 47 branch libraries at pen, but also complete information regarding the problem of paper acidity, ranging from the history of papermaking to the university departments), consists of nearly 2 mil- methods of paper mass deacidification. Since the pH-pens lion volumes. are not in common use in Poland, this home-made product was warmly welcomed by the community of conservators The acidity of books was tested with a pen filled with and has helped to promote the problem of deteriorating a water solution of chlorophenol red1. This indicator collections of libraries and archives.

283 Workshop 4

1998, and finally to only 0.7% in 2001. These find- 60 1.8 ings correspond with changes in the Polish paper in- acidic new acquisitions acid-free acquisitions 50 1.5 dustry. In the years 1995 and 1996, major paper mills total number of books were privatised, and shifted to modern, more eco- total number of acidic books 40 1.2 nomical acid-free technology. 30 0.9 By applying a linear interpolation, missing percentage values were calculated for the years for which acidity 20 0.6 was not tested. This interpolation is expected to give accurate results, since where the time span between 10 0.3 the test years was large (10 years), the measured per-

0 0.0 number of books (in millions) Total centage was nearly constant, and for the period of rap- Number of new acquisitio (in thousands) id changes in acidity the pH of books was tested every 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 second year. In this way, the amount of work neces- Year sary for the evaluation of the whole collection was re- Figure 2. The number of books at the Jagiellonian Library duced considerably. for years 1955–2001. Knowing the number of books which came to the (UMM Lib. – 400 000 volumes). In this study, the acid- Jagiellonian Library from its records, and the per- ity of books was checked for every year from 1990 to centage of acidic books in this set (measured or es- 2001, which was a period of rapid change according timated as explained above), it is possible to calcu- to the results obtained for the Jagiellonian Library. late the number of acidic books for a given year, and The number of tested titles of Polish origin was 553 by summing up these values, for the whole collec- for the Chem. Library, and 508 for UMM Library. The tion. Bars in Figure 2 represent the number of new results from all the libraries in question are summa- acquisitions for a given year, the black part of a bar rized in Table 1 and Figure 3. corresponding to the percentage of books whose paper is not acidic. Both lines drawn in Figure 2 The general trend for all the libraries was the same, show cumulative numbers – the total number of from nearly 100% acidic books at the beginning of the books in the Jagiellonian Library grew steadily to 1.8 last decade of the twentieth century, to zero, or almost million in the year 2001 (dark squares), but the num- zero by the year 2001. One could attribute the observed ber of acidic books stabilised in 1996 to the value of discrepancies in the measured values to differences in 1.5 million volumes (white squares). the fractions of acidic books between the libraries stud- The conclusion drawn from this evaluation is partly ied. In such a case, our assumption that all libraries in optimistic – although the large part of the library hold- Poland should follow the pattern of the Jagiellonian Li- ings is acidic (about 83% of books from the main col- brary would fail. But because standard errors for frac- 3 lection), the number of books endangered by the acid tions estimated with small samples are high , our hy- catalysed degradation has stopped growing. pothesis cannot be rejected on this ground.

As was said, the Jagiellonian Library has the status of 100 a and collects at least two copies of Jagiellonian Library Faculty of Chemistry Library every material printed in Poland (in the case of books, 80 UMM Library this rule is strictly followed). Thus, the book collection of any other library in Poland could be considered a 60 sub-set (smaller or equal in the number of owned ti- 40 tles) of the holdings of the Jagiellonian Library. If this assumption holds true, the characteristic curve of pa- 20 per acidity presented in Figure 1 should apply to all 0 Percentage of acidic books [%] other Polish libraries. This postulated universal nature 1990 1991 1992 1993 1994 19951996 1997 1998 1999 2000 2001 2 (universal, of course, on a national scale ) of the ob- Year tained curve was tested in other Cracow libraries. Two libraries were chosen – a small departmental li- Figure 3. The percentage of acidic books at three libraries brary at the Faculty of Chemistry of the Jagiellonian of Cracow. University (Chem. Lib. – 30 000 volumes) and the main library in the University of Mining and Metalurgy 3 For example, for the year 1994 the percentage of acidic books at the Jagiellonian Library is 86.6% ± 2.2%, at the 2 In other countries the situation is different. For example, in UMM Library 83.0% ± 15.9% and at the Chem. Library Switzerland a similar change in paper acidity was observed 70.8% ± 20.0%. The standard of error was calculated at during the years 1985–90 (BLÜHER 2002). In the USA 91% of a level of 0.05 significance, according to the equation: about 5000 books tested at the Penn State Library (KELLER- SE=1.96 × [p × (1-p)/n]1/2, where p denotes the fraction of MANN 1999) and printed between 1990–1992 were acid-free. acidic books, and n size of the sample (KENDALL, 1966)

284 The conservation of cultural heritage for sustainable development

Table 1. Results of acidity measurements for the years 1990–2001 from three Cracow libraries: the Jagiellonian Library (Jag. Lib.), the Library of the Faculty of Chemistry of the Jagiellonian University (Chem. Lib.) and the Main Library of the University of Mining and Metallurgy (UMM).

Number of tested books Percentage of acidic books [%] Jag. Lib. Chem. Lib. UMM Jag. Lib. Chem. Lib. UMM 1990 – 46 49 – 97,8 100,0 1991 – 4550 – 95,698,0 1992 1000 44 50 88,7 88,6 84,0 1993 – 44 48 – 88,6 62,5 1994 1000 47 48 86,6 83,0 70,8 1995 – 50 51 – 68,0 84,3 1996 1000 44 49 15,4 9,1 18,4 1997 – 50 55 – 4,0 0,0 1998 1000 49 20 3,52,0 0,0 1999 – 49 17 – 0,0 0,0 2000 – 48 22 – 0,0 0,0 2001 2500 37 49 0,73 0,0 0,0

Conclusions SPARKS P.G., ‘Technical Considerations in Choosing Mass Deacidification Processes’, Council on Library and Informa- By using a very simple and inexpensive test, essential tion Resources, 1990, http://www.clir.org/pubs/abstract/ information about the condition of books at one of the pub8.html. main libraries in Poland was obtained. The character- ‘The Deterioration and Preservation of Paper: Some Essen- istic pattern of changes in book acidity over the stud- tial Facts’, Library of Congress, 2001, http://lcweb.loc.gov/ ied years was observed. With the use of a drawn preserv/deterioratebrochure.html. curve, the total amount of acidic books was calculat- ed, which adds up to 1.5 million volumes. Since 1998, Tomasz Łojewski* this number has practically stopped growing. A paral- lel study carried out in two smaller libraries has Faculty of Chemistry, Jagiellonian University, proved that the obtained results can be extended to ul. Ingardena 3, 30-060 Kraków, Poland other Polish libraries, and the total number of acidic e-mail: [email protected] books waiting for rescue by a mass deacidification Graduated in chemistry at the Jagiellonian Universi- treatment can now be easily evaluated. ty, received his PhD degree there in 1999, working till then in the field of heterogenous catalysis. His current research focuses on the mechanisms of cel- References lulose deterioration, the methodology of accelerated BLÜHER A. and VOGELSANGER B., ‘Mass Deacidification ageing, and techniques of mass-scale deacidification of Paper’, Chimia, 55, 11, 981-989, 2001. of paper. BLÜHER A., private communication, 2002. KELLERMAN L.S., ‘Combating Whole-Book Deterioration: The Rebinding & Mass Deacidification Program at the Penn State University Libraries’, Library Resources and Technical Andrzej Barański Services, 43, 3, 1999. Faculty of Chemistry, Jagiellonian University, KENDALL M.G. and UDNY YULE G., An Introduction to the Theory of Statistics, London, Chapter 17, 1958. ul. Ingardena 3, 30-060 Kraków, Poland MCCRADY E., ‘pH Pens and Chlorophenol Red’, 1995, e-mail: [email protected] http://palimpsest.stanford.edu/byorg/abbey/phpens.html (accessed October 1, 2002). Bibliography on acidic paper problem (sources on-line, ac- Krzysztof Frankowicz, Zbigniew Harnicki cessed October 1, 2002): and Zbigniew Koziński PORCK H.J., ‘Mass deacidification: An update of possibilities and limitations’, European Commisssion on Preservation and Jagiellonian Library Access, 1996, http://www.knaw.nl/ecpa/PUBL/PORCK.HTM. al. Mickiewicza 22, 30-059 Kraków, Poland RHYS-LEWIS J., ‘The Enemy Within! Acid Deterioration of e-mail: [email protected] our Written Heritage’, British Library, 2001, http://www.bl.uk/ concord/proj99report1.html.

285