The document discusses research on assessing damage to historical parchment using various techniques including dynamic mechanical analysis, atomic force microscopy, micro-thermal analysis, and Fourier transform infrared spectroscopy. The research aims to improve damage assessment and provide a database of characterized samples. Accelerated aged samples and historical samples from various archives were studied. Different techniques provide markers of damage at various structural levels. Correlation was found between measurements and rankings of damage agree across techniques.

1. CRP 2008 CONSERVATION AND RESTORATION OF PARCHMENTS International Seminar & Workshop Turin, 3-5 September 2008, Italy Mechanical and Spectroscopic Analysis with Scanning Probe Microscopy for Damage Assessment of Historical and Accelerated aged collagen-based archival materials Marianne Odlyha Birkbeck College,Thermal Methods and Conservation Science,University of London

2. Background EC project “Improved Damage Assessment of Parchment” IDAP, EVK4-CT-2001-00061. The aim of the project was to improve damage assessment and provide a database of well characterised historical and accelerated aged parchment samples together with procedures to assess damage at various levels according to the hierarchical structure of collagen. http://www.idap-parchment.dk/

3. Samples IDAP project Accelerated aged samples (a) RH and T (40-80%RH and 40-80 ° C) (b) inorganic pollutants and (c) acetic acid vapour. Historical samples School of Conservation and Royal Danish Library, Copenhagen,Denmark, National Archives,Scotland, Archivio di Stato, Florence, Italy, Municipal Archive, Segovia, Spain. OPERA project State Archives of Turin and Genoa

4. Study of state of collagen in parchment Manuscripts and bookbindings Macroscopic level Microscopic level Nanoscopic level Molecular level www.idap-parchment.dk Mesoscopic level

5. Studies for IDAP Project at Birkbeck determined of damage indicators (order to disorder) at bulk nano molecular level Mechanical: has provided damage indicators in terms of collagen polymer and its response to moisture (%D,shrinkage, stiffness, and viscoelasticity). Information on side chains of collagen (polar/apolar) Thermogravimetric: measurement of fillers (inert & CaCO3). Broadening of temperature range over which weight loss occurs indicator of denaturation Solid state 13 C NMR: evidence of gelatinisation (only a few samples were in this category),and presence of lipids. ATR/FTIR: Amide I loss of ordered helical structure (some correlation with AA analysis), and changes in cross-linking. Micro-thermal analysis shows broadening of degradation processes. Ranking of damage is possible. Atomic Force Microscopy: possible to measure collagen D-spacing . Used to rank damage.

6. Measurement Technique and Markers of Damage Technique : Controlled environment Dynamic Mechanical Analysis (DMA) Function : Measures the effect of controlled changes in RH on the mechanical properties (modulus, extension) of parchment. Typical sample size 5mms free length, 4-5mms wide and 0.15-0.4 mms thick Direction where known head to tail Samples were clamped in a DMA analyser and subjected to an increase in RH (1%/min) from 10-80%RH at constant T

7. Typical result obtained on sample of parchment (goat unaged) Experimental details: sample was subjected to increase in RH from 20% to 80%RH. It was kept at 80%RH for 30mins and then decreased at 1%/min Plot of Elastic Modulus (stiffness) vs time (dark blue) and RH vs time (Yellow) Modulus T mins RH

8. ASGE_29_1 (1489) back cover flap samples were pre-dried in desiccator OPERA project samples : Bookbindings of the Series “ Diversorum ” from the “Secret Archives” Collection. State Archives of Genoa. Modulus vs RH Extension vs RH

9. OPERA Project THE PARCHMENT ROLLS OF CHATELAIN’S FINANCIAL ACCOUNTS (CASTELLANIE) State Archives of Turin ASTO 4-1: 1467-1469 (goat) sewing border on the recto part; ~a: (22 x 0.4) cm + b: (20 x 0.6) cm seems to be in good condition (a: thin; b: thin, soft, white) Modulus vs RH Extension vs RH

10. Bookbindings of the Series “ Manuali del Senato ” State Archives of Genoa. ASGE_2_2 (end of XIVth-beginning of XVth ) - seems to have suffered water damage - re-used in 1557 Modulus vs RH Extension vs RH

11. IDAP project database Effect of RH on mechanical properties of historical samples Displacement (%) vs Time (min) /RH (%) (a) Reference sample, (b) National Archives of Scotland (SC118) (c ) Archivio di Stato Florence (SC173:1) (d) School of Conservation,Copenhagen (S17:1) (e) (School of Conservation,Copenhagen (SC75:2)

12. % variation IDAP report Damage classification of historical parchments according to DMA-RH IDAP project Damage categories School of Conservation Copenhagen National ArchivesScotland Archivio di Stato Florence 1: Not damaged 0 - 20% SC69:4, SC56:1, SC38:1 SC116 N/A 2: Slightly Damaged 20 - 44% SC56:2, SC59:1, SC82:3 SC114, SC115, SC118, SC120 SC164, SC165:1&2 SC175:1 3:Considerably Damaged 44 - 70% SC17:1 , SC38SC58:1, SC77:1,SC72SC32, SC73: SC117, SC119, SC122 SC168, SC173:1 , SC175:2 4: Severely Damaged 70 - 100% SC16, SC18, SC31:1, SC35,SC59:2SC73:1 SC75 N/A SC163, SC172, SC173:2

13. Factors which influence the effect of RH on the mechanical properties Parchment manufacture : length of time in water bath, chemicals used, effectiveness of fat removal, amount of tension applied in parchment making. State of degradation of parchment : with increased age or increased exposure to environmental extremes, there may be more extensive oxidation of proteins, oxygen-induced cross-linking, increased gelatinization, and an increase in lower molecular weight fractions due to hydrolysis. These modifications may affect the tensile properties of the parchment. Extensive chain-scission and denaturation are associated with extreme brittleness of parchment. E.F.Hansen et al “The Effects of Relative Humidity on some physical properties of modern vellum” JAIC (1992) 31 No.3 325-342

14. SC69:4 (black) control CR31 (pink) SO 2 4 weeks 16weeks exposure to NO 2 gave similar result to CR31 Lower values of displacement /extension (%) occurred for the aged samples where collagen was damaged. Controlled Environment Dynamic Mechanical Analysis IDAP Unaged (black) and accelerated aged (pink) parchment (D%) vs time (mins)/ RH (%)

15. In the IDAP report ranking of the samples is given according to maximum and minimum values of slope (%D vs time). Sample set from database is shown below. Note variation in values for reference samples The effect of denaturation on RH response was studied by thermally denaturing a sample (heat to 220 º C). Value for the slope 15-40mins (1 st column) was minimum (c.0.007).

16. Samples OPERA project (Table) Samples IDAP project a) Reference sample, (b) National Archives of Scotland (c ) Archivio di Stato Florence (d) School of Conservation,Copenhagen (e) (School of Conservation,Copenhagen ASGE_11_2 lipid containing

17. Structure of collagen D spacing nm

18. “ Damage Assessment of Collagen in historical parchment with scanning probe techniques” J de Groot Ph.D thesis Birkbeck University of London Atomic force microscopy AFM (Unaged parchment) Thermally denatured parchment after heating to 220ºC Atomic Force Microscopy Human skin collagen has an average cross-banding periodicity D of 64 ± 5 nm

19. Change in D-spacing with Temperature Values 30-170 º C Thermal Analysis of parchments D.Fessas,M.Signorelli,A.Schiraldi,C.J.Kennedy,T.J.Wess Value at 220 º C J de Groot Ph.D thesis

20. Intstrumental Technique Atomic Force Microscopy (AFM) A tip is scanned over the surface forming an image of the surface

22. A novel algorithm was developed that can estimate the intactness of the periodic banding in the entire image This algorithm uses the Fourier Transform that converts an image into a two dimensional (2D) spatial frequency image (J de Groot Ph.D thesis). Estimate intactness of the periodic D-banding (IDAP report )

23. A 2 weeks B 4 weeks C 8weeks D 16 weeks Effect of SO 2 ageing on model parchment (AFM) CR31 CR33

24. AFM- Peak Area measure of intactness of periodic banding vs Ts (shrinkage T) (Larsen et al., 2006) for selected historical samples Ref SC81:5(red) SC162 13 th cent Segovia SC175:2 (Florence)

25. Acetic acid vapour effect on fibril distributions in rat tail collagen

26. AFM - basic operation 4 quadrant photodetector laser 3 element piezo crystal array in scanner head sample silicon cantilever, length 0.1 - 1 mm Ultra-sharp tip, radius ca. 10 nm Force feedback loop x y z

27. Historical sample (13 th cent) SC162 (IDAP database) Municipal Archive in Segovia-Spain- Concession of rights and privileges by Alfonso X Visual categorisation of damage Slightly damaged IDAP database Sample SC162 Ts= 55.9°C From ATR / FTIR damage category (2) grain side. From AFM damage category also (2) (J de Groot) Fibre network x 100 transmission

28. Historical sample (13 th cent) SC162

29. Collagen banding in 13 th cent manuscript SC162 Measurements made directly on parchment no sampling required.

31. Micro-thermal Analysis -  TA Image from www.anasys.co.uk

32. Accelerated aged CR05 (light 170Klux 32 hrs) and CR33 16 weeks SO2 Derivative Power mW/C vs T

33. Damage markers and Ts for accelerated aged parchment samples measured with micro-TA. Values indicated with * differed significantly different from the unaged control samples IDAP Quantification of parchment damage by micro-TA SO 2 aged and RH,T aged (80C 40%RH)

34. ATR-FTIR of parchment sample (unaged) and after thermal denaturation (220 ° C) Unheated Heated to 220 ° C AFM images

35. ATR/FT-IR spectra of both flesh (dot) and grain (full) sides of SC73.1&2 18 th cent calf Visual slightly damaged Ts=50.8 and 44.5 ° C Historical samples IDAP data base e.g 18 th century bookbinding SC73:1 Ranking of damage made on basis of change in shape of Amide 1 (ratio 1660:1630) C. Theodorakopoulos and M.Odlyha “Studies on Archival Parchment by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy” Studies in Conservation (paper submitted)

36. ATR/FT-IR spectra at two locations of the same sample: SC175:1 (dash) and SC175:2 (full). In SC175:1 the amide I peak is at (a) and this is moved to (b) in SC175:2 and broadened to (c), in SC175:2 lipid (d) and carbonate (e) are present. SC175:1 SC175:2 Ts = 35.9C Historical bookbinding SC175:1 and 2

37. IDAP report SC169, SC172, SC173:1 , SC175:2 SC122, SC120 SC17:2, SC75:2 >20% 4: Very Damaged N/A SC114, S124, SC125 SC56:1,SC24, SC18 ,SC38:1,SC72:1,SC72:2,SC75:1, SC73:2 12 - 20% 3: Considerably Damaged SC164, SC165:1 SC166, SC168, SC173:2, SC175:1 SC116, SC118, SC119 SC17:1, SC31:1, SC32, SC58:2, SC59:1, SC70:1, SC76:1,SC77, SC16, SC35, SC58:1, SC38:2 5 - 12% 2: Slightly Damaged SC163, SC165:2 SC115, SC117, SC123 SC59:2, SC69:2, SC70:2, SC76:1 0 - 5% 1: Not damaged Archivio di Stato Florence National Archives, Scotland School of Conservation, Copenhagen % Change 1660:1630 Damage categories Damage classification of historical parchments according to ATR-FTIR

38. Current OPERA project samples Note ASGE 2_2 Also gives low D (%) by DMA_RH

39. Opera project samples ASGE11-2 lipid containing (13C SSNMR) shows high damage C.Ghioni, J.C.Hiller, C.Kennedy, A.E.Aliev, M.Odlyha, M.Boulton and T.J.Wess “Evidence of a distinct lipid fraction in historical parchments: a potential role in degradation” J Lipid Res 46 (2005) 2726-2734

40. Conclusions Damage and differences in damage were observed in samples from different archives, and from within the same archive for samples with differences in lipid and inorganic content, and whether they had been previously used as manuscripts or bookbindings. Correlation between periodic D spacing (determined from AFM) and the mechanical properties of parchment such as its stiffness and readiness to take up moisture was observed. Previous water damage influences this response. The database obtained in IDAP allows comparison of damage ranking by AFM and micro-TA data with e.g Ts determination, and then ATR-FTIR and mechanical. Visual assessment of damage can be misleading. Future work could include optimising values (RH) for storage and display of 30% RH has been suggested as the optimum condition for an object for which the long-term preservation of the intact collagen is of greatest concern. Also optimising RH used in conservation treatment.

41. Acknowledgements Coauthors C.Theodorakopoulos (ATR/FTIR), J de Groot, L.Bozec and Prof M.Horton (AFM and micro-TA) The authors are grateful to the European Commission DG-RTD 5 th Framework “City of Tomorrow and Cultural Heritage“ for funding the IDAP project (contract no. EVK4-CT-2001-00061). Coordinator (Dr. Rene Larsen) and fellow participants in IDAP and Coordinator of OPERA project (Prof G.Della Gatta and Dr.R.Larsen) Controlled environment DMA Dr.G.Foster, Smithers Rapra, and Dr.J.Duncan Triton Technology We also thank Victoria Smith for arranging sampling in Spain and Spanish translation of IDAP web page