Goudleer, c. 1660, Rijksmuseum

Caractérisation des effets de la chaleur sur des cuirs de tannage végétal et développement d’une stratégie de restauration par voie enzymatique par Izquierdo (2015)

Izquierdo, Eléonore, Caractérisation des effets de la chaleur sur des cuirs de tannage végétal et développement d’une stratégie de restauration par voie enzymatique, PhD thesis, Université de Cergy Pontoise, 2015. 

URL / PDF (HAL)

Resumé:

L'exposition à la chaleur, notamment lors d'incendies est particulièrement dévastatrice et dans le cas d'objets du patrimoine elle entraine la destruction de tout ou partie de ces témoins du passé. Notre étude porte sur les effets de la chaleur sur le cuir, matériau largement présent dans les collections patrimoniales. A ce jour, aucune méthode de restauration permettant d'inverser les effets de la chaleur n'a été développée. Le premier objectif de notre étude est d'évaluer les effets d'une exposition à une chaleur sèche par une caractérisation systématique d'échantillons avant et après exposition à la chaleur. Des échantillons modèles, issus d'une même peau de veau de tannage végétal connu, ont été utilisés et caractérisés à différentes échelles structurales par un large ensemble de techniques physico-chimiques et biochimiques avant et après chauffage.Au-delà du brunissement et de la rétraction visible du cuir, la chaleur induit de nombreuses altérations au niveau de la structure du matériau, notamment, une perte de masse, une fonte des structures cristallines, une augmentation de l'hydrophobie ainsi qu'une rigidification. Une partie de ces changements sont attribués à l'agrégation protéique mise en évidence par cette recherche.Le second objectif était de développer une méthode de restauration innovante basée sur l'utilisation de molécules biologiques afin de respecter la nature de l'objet. Des enzymes de type protéase, capables de rompre les agrégats protéiques ont été utilisées. Un des défis est d'apporter suffisamment d'eau, nécessaire pour l'activité de l'enzyme, sans mouiller le cuir pour éviter tout dommage supplémentaire. Plusieurs supports d'application de la protéase ont été testés. Avec une émulsion enzymatique les résultats obtenus ne mettent en évidence ni coloration, ni rétraction et dans certains cas un gain de souplesse est observé. Des résultats encourageants ont également été obtenus dans le cas d'un cuir de veau historique (XIXe siècle). Des mesures complémentaires ont fait attribuer ces propriétés principalement à l'émulsion elle-même, cependant des mesures à plus long terme semblent mettre en évidence un effet positif de l'enzyme sur le gain de souplesse. Sous réserve de nouvelles caractérisations à des temps plus longs, le traitement élaboré pourrait constituer un nouveau support de restauration par voie biologique.

“A shagreen walking stick" by Silverman (2015)

Catherine Silverman, “A shagreen walking stick", ICON news: the magazine of the Institute of Conservation 59 (2015), pp. 33-36. 

URL (Icon, free access) 

This conservation work was also presented in May of 2014 as a post of the West Dean College-School of Conservation Blog.

URL

Vue intérieure de la tannerie Raillard et Schaefer, Mulhouse, France (1900)

                                          URL (Gallica)

A comparative study of Roman-period leather from northern Britain by Douglas (2015)

Douglas, Charlotte R., A comparative study of Roman-period leather from northern Britain, MPhil(R) Thesis, University of Glasgow, 2015.

URL (University of Glasgow Theses)

Abstract:

This thesis draws together all of the data on Roman-period leather from northern Britain and conducts a cohesive assessment of past research, current questions and future possibilities. The study area comprises Roman sites on or immediately to the south of Hadrian’s Wall and all sites to the north. Leather has been recovered from 52 Roman sites, totalling at least 14,215 finds comprising manufactured goods, waste leather from leatherworking and miscellaneous/unidentifiable material. This thesis explores how leather and leather goods were resourced, processed, manufactured and supplied across northern Britain. It considers the potential of inscriptions and stamps to provide insights into the leather trade. It also considers the contribution that the study of footwear might make to our understanding of the demography of Roman settlements, shedding light in particular on evidence which suggests that military communities may have been more diverse than previously thought, and that there were women and children living on the northern fringes of the empire long before the Antonine Wall and its civilian communities were established.

“Feasibility of ultrafast picosecond laser cleaning of soiling on historical leather buckles” by Elnaggar et al (2016)

Elnaggar, Abdelrazek; Fitzsimons, Paul; Lama, Anne; Fletcher, Yvette; Antunes, Paula; Watkins, K. G., “Feasibility of ultrafast picosecond laser cleaning of soiling on historical leather buckles”, Heritage Science 4 (2016) 30.

DOI:10.1186/s40494-016-0104-3 (SpringerOpen, open access)

Abstract:

The aim of the research is to present a system recently developed and used for automated cleaning of artworks and to examine the suitability of using this ultrafast and precise computed-scanning picosecond laser (1064 nm) with a repetition rate of 10 kHz and a temporal pulse length of 10 ps for the removal of soiling from leather buckles without damaging the leather substrate. Preliminary tests will be performed with the model artificially aged vegetable tanned samples to determine the leather damage threshold fluence and the soiling ablation threshold fluence before using a laser for the removal of the soiling from a historical leather buckle. As laser cleaning requires a physical parameterization for optimization of cleaning accompanied with an assessment of the morphological and chemical changes of leather, an investigations were performed to determine the leather damage and ablation threshold fluences of artificially aged and historical vegetable tanned leather using a number of analytical techniques including differential scanning calorimetry, optical microscopy, scanning electronic microscope with energy dispersive X-ray analysis, colorimetry and Fourier transform infrared spectroscopy have been used. Following optimization trials of the picosecond laser cleaning parameters on model leather samples, satisfactory removal of the soiling over the historical leather surface is achieved.

“Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments” by Latour et al (2016)

Latour, Gaël; Robinet, Laurianne; Dazzi, Alexandre; Portier, François; Deniset-Besseau, Ariane; Schanne-Klein, Marie-Claire, “Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments”, Scientific Reports 6 (2016) 26344.

DOI:10.1038/srep26344 (Nature.com, open access)

Abstract:

This paper presents the correlative imaging of collagen denaturation by nonlinear optical microscopy (NLO) and nanoscale infrared (IR) spectroscopy to obtain morphological and chemical information at different length scales. Such multiscale correlated measurements are applied to the investigation of ancient parchments, which are mainly composed of dermal fibrillar collagen. The main issue is to characterize gelatinization, the ultimate and irreversible alteration corresponding to collagen denaturation to gelatin, which may also occur in biological tissues. Key information about collagen and gelatin signatures is obtained in parchments and assessed by characterizing the denaturation of pure collagen reference samples. A new absorbing band is observed near the amide I band in the IR spectra, correlated to the onset of fluorescence signals in NLO images. Meanwhile, a strong decrease is observed in Second Harmonic signals, which are a structural probe of the fibrillar organization of the collagen at the micrometer scale. NLO microscopy therefore appears as a powerful tool to reveal collagen degradation in a non-invasive way. It should provide a relevant method to assess or monitor the condition of collagen-based materials in museum and archival collections and opens avenues for a broad range of applications regarding this widespread biological material.

“Study of the effect of tannins and animal species on the thermal stability of vegetable leather by differential scanning calorimetry” by Carşote et al (2016)

Carşote, Cristina; Badea, Elena; Miu, Lucretia; Gatta, Giuseppe Della, “Study of the effect of tannins and animal species on the thermal stability of vegetable leather by differential scanning calorimetry”, Journal of Thermal Analysis and Calorimetry 124(3) (2016) pp. 1255–1266.

DOI:10.1007/s10973-016-5344-7 (SpringerLink, restricted access)

Abstract:

Micro-differential scanning calorimetry was used to reveal the deterioration patterns of collagen in vegetable-tanned leather. The influence of both the tannin type, i.e. hydrolysable or condensed, and collagen animal species, i.e. calf and sheep, was investigated. Comparison with the behaviour of unmodified collagen in parchment was made to explain the thermal destabilisation and denaturation of the chemically modified collagen in leather. Both leather and parchment were subjected to accelerate ageing by heating at 70 °C in controlled atmosphere at 30 % RH. The synergistic effect of the daylight exposure was studied by irradiating the samples in the visible domain with 4000 lx. The destabilisation effect induced by the hydrothermal ageing treatment was evident since the 8th day and reached a critical level after 32-day ageing time. The formation of damaged intermediate states with progressively lower thermal stability was the main feature of the deterioration pattern independent of the tannin type and collagen species. Quebracho-tanned calf leather was the most resistant against ageing, whereas chestnut-tanned sheep leather underwent de-tanning after a 32-day ageing period. Exposure to visible light irradiation induced an evident thermal stabilisation due to cross-link formation. The balance between thermal stabilisation and destabilisation processes in leather during visible light exposure was influenced by the tannin type.

"Caring for leather, skin and fur" by Carole Dignard and Janet Mason (2016)

"Caring for Leather, Skin and Fur" is a web resource of the Canadian Conservation Institute which presents key aspects of managing the care of leather, skin and fur objects in heritage collections based on the principles of preventive conservation and risk management. It outlines the different qualities and characteristics of leather, skin and fur and the causes of damage to these objects. It also provides examples of preventive conservation practice.

URL 1 / URL 2 (French version)

 

“An Improved Method of Tanning Leather” by Macbride (1778)

Macbride, David, “An Improved Method of Tanning Leather”, Philosophical Transactions of the Royal Society of London 68 (1778) pp. 111–130.

DOI:10.1098/rstl.1778.0008 (The Royal Society Publishing or JSTOR, free access)

Ioannis Costaei Dispvtatio qvod ex arte Coriariorvm infici aer possit, et pestis procreari (1580)

Costeo, Giovanni, Ioannis Costaei Dispvtatio qvod ex arte Coriariorvm infici aer possit, et pestis procreari, Venetiis, Apud Dominicum Farreum, 1580.

URL (Österreichische Nationalbibliothek)

"Variation in the sorption properties of historic parchment evaluated by dynamic water vapour sorption" by Popescu et al (2016)

Popescu, Carmen-Mihaela; Callum A. S. Hill; Kennedy, Craig; "Variation in the sorption properties of historic parchment evaluated by dynamic water vapour sorption", Journal of Cultural Heritage 17 (2016) pp.87–94.

Doi:10.1016/j.culher.2015.06.001 (ScienceDirect, restricted access)

Abstract:

Understanding the hydration of the collagen historic parchments is of great importance to the conservation and restoration processes. In this study, modern and historic (dated 1817 and 1769) parchments were investigated using dynamic water vapour adsorption/desorption (sorption) experiments. The relationship between the equilibrium moisture content against the relative humidity at constant temperature for two consecutive sorption cycles, the hysteresis and kinetic properties were analysed for different parchments from a historic archive. It was found that historical parchment samples exhibited higher equilibrium moisture content levels throughout most of the hygroscopic range and the hysteresis was greater than that of the contemporary sample. The samples were all found to obey parallel exponential kinetics for both adsorption and desorption. By applying the parallel exponential kinetic model, it was observed that the difference in the hysteresis is apparently mostly due to changes in the collagen matrix relaxation processes.

Skin Costumes Online

In October 2014 The Danish National Museum, in collaboration with the National Museum of Greenland and the Museum of Cultural History, Oslo, published the website Skin Costumes Online at http://skinddragter.natmus.dk/. This website is available both in Danish and in English.
 

Skin Costumes Online shows high-resolution photos and detailed information of outstanding and historic skin costumes from the indigenous peoples in Greenland, North America, North Scandinavia and Siberia.

Through the website easy access will be given to this rich cultural heritage, from museums' collections. 

This project was supported by The Nordic Culture Fund, Augustinus Fonden, Knud Rasmussen Fonden and the National Museum of Denmark through the research program Northern Worlds 2009-2013.​

"Degradation of collagen in parchment under the influence of heat-induced oxidation" by Mühlen Axelsson et al (2016)

Mühlen Axelsson, K.; Larsen, R.; Sommer, D. V. P.; Melin, R.; “Degradation of collagen in parchment under the influence of heat-induced oxidation: Preliminary study of changes at macroscopic, microscopic, and molecular levels”, Studies in Conservation 61(1) (2016) pp. 46–57.

DOI: 10.1179/2047058414Y.0000000140 (Taylor & Francis Online, restricted access)

Abstract:

This paper examines the impact of heat-induced oxidation for new and historical parchment with the purpose of improving diagnostic tools for use in practical parchment conservation. Oxidation was generated by heat aging at 120°C in a dry oven for 24, 48, and 96 hours, respectively. The degradation was assessed on all samples at macrolevel by measuring color changes, at microlevel by measuring the shrinkage temperature as well as by performing a visual assessment of the fibers’ morphology and determining the amount of damaged fibers, and finally, at molecular level where amino acid analysis was used to reveal changes in the oxidized collagen. The study shows that the heat-induced oxidation leads to significant color changes, decrease in hydrothermal stability, as well as changes in the amino acid composition. Surprisingly, the results show that the historical parchment is more sensitive towards dry heat oxidation on a molecular level than is the new parchment. Furthermore, for the first time, we can show that physical damage reflected in the morphological characteristics of fibers can be attributed to oxidation by dry heat.

La fábrica de curtidos en Santa María del Páramo (León). El curtido tradicional de las pieles en Castilla y León (2014)

Fernández Martín, Juan José; García García, Luis Antonio; Marcos González, David; Palazón Botella, María Dolores; Sánchez Pérez, Pablo; San José Alonso, Jesús, La fábrica de curtidos en Santa María del Páramo (León). El curtido tradicional de las pieles en Castilla y León, Junta de Castilla y León. Consejería de Cultura y Turismo (2014).

URL / PDF

Série Encyclopédique Glucq des leçons de choses illustrées, Imagerie d'Épinal n.º 3817, Cuirs & Tannerie

“Skin-Covered Masks from the Cross River Region of Nigeria and Cameroon at the National Museum of African Art: A Technical Study” by Owczarek (2014)

Owczarek, Nina, “Skin-Covered Masks from the Cross River Region of Nigeria and Cameroon at the National Museum of African Art: A Technical Study”, Journal of the American Institute for Conservation 53(3) (2014) pp. 182–197.

DOI:10.1179/1945233014Y.0000000025 (Taylor & Francis Online, restricted access)

Abstract:

Nineteen skin-covered masks from the Cross River region of Nigeria and Cameroon were studied at the National Museum of African Art. The construction of the masks are documented and compared against existing field literature. Results of analyses of the wood, skin, and surface applications are included, as well as detail images of construction features. In addition to visual examination, x-radiography, thin section, deoxyribonucleic acid, portable x-ray fluorescence, x-ray diffraction, and Fourier transform infrared analysis techniques were employed in the examination. For the most part, this study showed the skin-covered masks in the NMAfA collection support the basics of the field literature descriptions while also illustrating a wider variety in techniques and materials.

Crest mask, Cross River region of Nigeria, 19th-20th century, Smithsonian National Museum of African Art

“Saving our skins: long-term care of masks from the Cross River Region” by Julien (2000)

Julien, Sophie, “Saving our skins: long-term care of masks from the Cross River Region”, Journal of Museum Ethnography 12 (2000) pp. 115–124.
URL (JSTOR, restricted access)

Abstract:
This paper gives a conservation perspective on collecting and conserving ethnographic material in the museum context, using the example of the Horniman Museum's collection of skin-covered masks from the Cross River Area of Nigeria.

“Nanomaterials for the cleaning and pH adjustment of vegetable-tanned leather” by Baglioni et al (2016)

Baglioni, Michele; Bartoletti, Angelica; Bozec, Laurent; Chelazzi, David; Giorgi, Rodorico; Odlyha, Marianne; et al., “Nanomaterials for the cleaning and pH adjustment of vegetable-tanned leather”, Applied Physics A 122(2) (2016) pp. 1–11.

DOI:10.1007/s00339-015-9553-x (SpringerLink, restricted access)

Abstract:

Leather artifacts in historical collections and archives are often contaminated by physical changes such as soiling, which alter their appearance and readability, and by chemical changes which occur on aging and give rise to excessive proportion of acids that promote hydrolysis of collagen, eventually leading to gelatinization and loss of mechanical properties. However, both cleaning and pH adjustment of vegetable-tanned leather pose a great challenge for conservators, owing to the sensitivity of these materials to the action of solvents, especially water-based formulations and alkaline chemicals. In this study, the cleaning of historical leather samples was optimized by confining an oil-in-water nanostructured fluid in a highly retentive chemical hydrogel, which allows the controlled release of the cleaning fluid on sensitive surfaces. The chemical gel exhibits optimal viscoelasticity, which facilitates its removal after the application without leaving residues on the object. Nanoparticles of calcium hydroxide and lactate, dispersed in 2-propanol, were used to adjust the pH up to the natural value of leather, preventing too high alkalinity which causes swelling of fibers and denaturation of the collagen. The treated samples were characterized using scanning electron microscopy, controlled environment dynamic mechanical analysis, and infrared spectroscopy. The analytical assessment validated the use of tools derived from colloid and materials science for the preservation of collagen-based artifacts.

“The Chester leather industry, 1558-1625” by Woodward (1967)

Woodward, D. M., “The Chester leather industry, 1558-1625”, Transactions of the Historical Society of Lancashire and Cheshire 119 (1967) pp. 65–111.
PDF (The Historic Society of Lancashire & Cheshire)

La dorure sur cuir: reliure, ciselure et gaufrure en Allemagne par Stockbauer et Maul (1888)

Stockbauer, Jacob; Maul, Johannes; La dorure sur cuir: reliure, ciselure et gaufrure en Allemagne, 2 vol., Paris, B. Rouveyre (1888).

URL (Gallica)

“Detection of COL III in parchment by amino acid analysis” by Sommer and Larsen (2016)

Sommer, Dorte V. P.; Larsen, René; “Detection of COL III in parchment by amino acid analysis”, Amino Acids 48 (1) (2016) pp. 169–181.

DOI:10.1007/s00726-015-2074-2 (SpringerLink,restricted access)

Abstract:

Cultural heritage parchments made from the reticular dermis of animals have been subject to studies of deterioration and conservation by amino acid analysis. The reticular dermis contains a varying mixture of collagen I and III (COL I and III). When dealing with the results of the amino acid analyses, till now the COL III content has not been taken into account. Based on the available amino acid sequences, we present a method for determining the amount of COL III in the reticular dermis of new and historical parchments calculated from the ratio of Ile/Val. We find COL III contents between 7 and 32 % in new parchments and between 0.2 and 40 % in the historical parchments. This is consistent with results in the literature. The varying content of COL III has a significant influence on the uncertainty of the amino acid analysis. Although we have not found a simple correlation between the COL III content and the degree of deterioration, our results show that this question must be taken into consideration in future studies of the chemical and physical deterioration of parchment measured by amino acid analysis and other analytical methods.

“Proteins in Art, Archaeology, and Paleontology: from detection to identification” by Dallongeville et al (2016)

Dallongeville, Sophie; Garnier, Nicolas; Rolando, Christian; Tokarski, Caroline, “Proteins in Art, Archaeology, and Paleontology: from detection to identification”, Chemical Reviews 116(1) (2016) pp. 2–79.

DOI:10.1021/acs.chemrev.5b00037 (ACS Publications, restricted access)

“Quantifying degradation of collagen in ancient manuscripts: the case of the Dead Sea Temple Scroll” by Schütz et al (2013)

Schütz, R.; Bertinetti, L.; Rabin, I.; Fratzl, P.; Masic, A., “Quantifying degradation of collagen in ancient manuscripts: the case of the Dead Sea Temple Scroll”, Analyst 138(19) (2013) pp. 5594–5599.

DOI:10.1039/C3AN00609C (Royal Society of Chemistry, open access)

Abstract:

Since their discovery in the late 1940s, the Dead Sea Scrolls, some 900 ancient Jewish texts, have never stopped attracting the attention of scholars and the broad public alike, because they were created towards the end of the Second Temple period and the “time of Christ”. Most of the work on them has been dedicated to the information contained in the scrolls' text, leaving physical aspects of the writing materials unexamined. They are, however, crucial for both historical insight and preservation of the scrolls. Although scientific analysis requires handling, it is essential to establish the state of degradation of these valued documents. Polarized Raman Spectroscopy (PRS) is a powerful tool for obtaining information on both the composition and the level of disorder of molecular units. In this study, we developed a non-invasive and non-destructive methodology that allows a quantification of the disorder (that can be related to the degradation) of protein molecular units in collagen fibers. Not restricted to collagen, this method can be applied also to other protein-based fibrous materials such as ancient silk, wool or hair. We used PRS to quantify the degradation of the collagen fibers in a number of fragments of the Temple Scroll (11Q19a). We found that collagen fibers degrade heterogeneously, with the ones on the surface more degraded than those in the core.

"Parchment production in the first millennium BC at Seglamen, Northern Ethiopia" by Phillipson (2013)

Phillipson, Laurel; "Parchment production in the first millennium BC at Seglamen, Northern Ethiopia", African Archaeological Review 30(3) (2013) 285–303.
doi:10.1007/s10437-013-9139-y (SpringerLink, restricted access)

Abstract:

Traditional Ethiopian and European processes of parchment manufacture and their associated tools are described and compared with artefacts recovered from an important pre-Aksumite site at Seglamen, in the highlands of northern Ethiopia. Many close similarities of tools used at Seglamen in both the earlier and later phases of the pre-Aksumite, from about 800 BC, to implements used by present-day Ethiopian scribes attest to the systematic production of parchment at Seglamen and to cultural continuity over a period of almost three millennia.

"Curtimento de peles" por Leite (1912)

 

Leite, Manuel da Silva; "Curtimento de peles", Ilustração Portuguesa 350 (1912) 601-604.

PDF (Hemeroteca Digital de Lisboa)