Previous works of the authors have presented the changes in the optical, mechanical, and chemical properties of the oiled areas of the supports that occur upon ageing due to oil-binder absorption in works of art on paper and printed material. In this framework, transmittance FTIR analysis has indicated that the presence of linseed oil induces the conditions to promote the deterioration of the oil-impregnated areas of the paper supports. However, the analysis of oil-impregnated mock-ups did not provide detailed information about the input of linseed oil formulations and the different types of paper support on the chemical changes that occur upon ageing. This work presents the results of ATR-FTIR and reflectance FTIR, which were used for compensating the previous results, proving indications on the effect of different materials (linseed oil formulations, and cellulosic and lignocellulosic papers) on the development of chemical changes, thus, on the condition of the oiled areas upon ageing. Although linseed oil formulations have a determining effect on the condition of the oiled areas of the support, the paper pulp content appears to have an input to the chemical changes that occur in the system of paper–linseed oil upon ageing. The results presented are more focused on the oil-impregnated mock-ups with cold-pressed linseed oil since results have indicated that this causes more extended changes upon ageing.

Condition assessment of works of art created with oil media on paper could be a complex matter when presenting problems of damage due to the absorption of oil binders by the paper support, since they depend on several factors and occur in variable conditions. The present work refers to the results of an investigation on the effect of linseed oils on the color, opacity, morphology, tensile strength, and chemical properties of lignocellulosic papers, in comparison to that of pure cellulosic papers. Lignocellulosic papers are involved in research on new, yet significant, parameters that might influence the behavior of the oil-impregnated areas of the supports upon aging. The research was applied to mock-ups, made of two types of lignocellulosic paper impregnated with three types of linseed oil and subjected to accelaratated ageing in specific conditions of relative humidity and temperature in closed environment. The research involved colorimetry, opacity, tensile strength, pH measurements, SEM, FTIR, and VOC analysis with GC-MS. The results indicated that thermal-humid ageing caused the gradual darkening of the oil-impregnated mock-ups, alterations in opacity, and decrease of pH values, depending mainly on the formulation of linseed oil, as well as a reduction in tensile strength. FTIR analysis results indicated that the chemical changes that occur upon ageing supported the recorded optical and mechanical alterations, while VOC emissions are both associated with the paper type and the kinetics of degradation of the different types of linseed oil.

Oil media on paper, such as oil paintings, sketches, prints, and books, occasionally present problems associated with the effect of oil medium on the paper support, raising a composite matter of condition assessment as it depends on several factors. The present work examines the effect of linseed oil on paper and, in particular, the changes caused by three types of linseed oil on the optical, morphological, mechanical, and chemical properties of pure cellulosic paper, employing mock-ups submitted to artificial ageing in controlled conditions of relative humidity and temperature in airtight vessels. The study involved colorimetry, opacity, tensile strength, pH measurements, SEM, FTIR, and VOC analysis with GC-MS. Processing of the results has so far indicated that thermal-humid ageing caused the gradual darkening of the oil-impregnated mock-ups, as well as alterations in opacity, intense fall of pH values, and severe reductions in tensile strength, while linseed oil processing during manufacture has a significant impact. FTIR spectra have indicated that chemical changes upon ageing are in accordance with those of optical and mechanical changes, while VOC emissions are mostly associated with the drying and degradation of the different types of linseed oil.

This article explores issues concerning the conservation of the post-Byzantine Patriarchal sigillia (deeds on parchment) in the collections of the General State Archives of Greece. These are documents of considerable size, often with an elaborate tongue-like projection and a pedant lead seal, typically folded to create a small package. Various materials are involved in their structure, which affects their condition. Folding practices have resulted in severe creasing and planar distortions, while the hanging system and the pendant seal often cause serious mechanical damage. The component parts could not be separated during conservation procedures, influencing decisions about treatment and intervention. Opening the substrate flat without altering or destroying original features, or affecting the materials involved, is a challenging task. Storage and hinging methods were developed to provide support without loss of original features. Résumé «Approches de la conservation des sigillia patriarcaux sur parchemin des Archives Nationales de Grèce» Cet article explore les questions relatives à la conservation des sigillia patriarcaux post byzantins (actes sur parchemin) dans les collections des Archives Nationales de Grèce. Ce sont des documents de taille considérable, souvent avec une languette élaborée et un sceau pendant en plomb, habituellement pliés pour créer de petits paquets. Des matériaux variés sont impliqués dans leur structure, ce qui affecte leur état de conservation. Les pratiques du pliage ont eu pour conséquence des plis sévères et une déformation de la surface, tandis que le sceau pendant et son mode de fixation ont souvent causé des dommages mécaniques. Les éléments ne pouvaient pas être dissociés pendant les procédures de restauration, influençant les décisions de traitement et d'intervention. L'ouverture et la mise à plat du support sans altérer ni détruire les caractéristiques originales, ni affecter les matériaux impliq... Zusammenfassung ,,Verschiedene Zugänge zur Konservierung/Restaurierung Patriarchischer Sigillia auf Pergament in den General State Archives of Greece“ Dieser Artikel untersucht Themen, die mit der Konservierung/Restaurierung von patriarchischen Sigillia (Urkunden auf Pergament) in den General State Archives of Greece verbunden sind. Es handelt sich bei diesen Objekten um Dokumente, die ziemlich groß sein können, oft mit einer komplizierten zungenartigen Projektion und einem bleiernen Hängesiegel, typischerweise zu einem kleinem Paket gefaltet. Verschiedene Materialien sind also in diese Struktur eingebunden, was oft den Zustand beeinflusst. Faltungen haben oft schwere Knicke und Verwellungen zur Folge, ein hängendes Lagerungssystem und auch das Hängesiegel haben oft schwere mechanische Schäden verursacht. Die verschiedenen Komponenten konnten während der Konservierung/Restaurierung nicht getrennt werden, was natürlich die Entscheidungen über Intervention und Behandlung beeinflusste. Das Objekt zu öffnen, ... Resumen “Enfoques para la conservación de la Sigillia Patriarcal en pergamino del Archivo General de Estado de Grecia” Este artículo explora los aspectos relativos a la conservación de la post-bizantina “Sigillia Patriarcal” (escrituras en pergamino) de las colecciones del Archivo General del Estado de Grecia. Se trata de documentos de un tamaño considerable, a menudo con un saliente muy elaborado (en forma de lengua) y un sello de plomo colgante, normalmente plegado para crear un envoltorio pequeño. Esta estructura contiene diversos materiales que afectan su condición. La práctica del plegado ha producido tanto serias grietas como distorsiones por las dobleces, mientras que el sistema de suspensión y el sello colgante a menudo han causado daños mecánicos graves. Los componentes no podían separarse durante los procedimientos de conservación, y por tanto influyeron en las decisiones sobre el tratamiento y la intervención. Además, abrir el sustrato plano, sin alterar o destruir sus características originale...