X-rays Absorption Spectroscopy (XAS), for its features of high elemental selectivity, spatial resolution and non- destructivity, is a useful tool to study materials that form and decorate art object and to identify different degradation processes that can occur in works of art.In this study, it will be investigated a typical phenomenon of paper alteration called foxing, which appears as spots of variable dimensions generally colored from lemon yellow to dark-brown with sharp or irregular edges. Over the years, in fact, paper undergoes a series of alterations caused both by external and internal factors leading to cellulose degradation. This degradation is one of the greatest problems for the conservation of paper supports such as archival documents, books and artistic works. Degraded papers can show an evident fragility, a general yellowing and the formation of foxing spots that can, in some cases, not only damage the aesthetic of the object, but also compromise the readability of the text or the artistic works. The understanding of the different chemical processes underlying this degradation is of great importance to prevent further damage and to choose the appropriate restoration method. The foxing spots are generated by a complex mechanism based on the oxidation of iron or copper ions (chemical hypothesis) or on micro-organism based processes (microbiological hypothesis). By XAS we have investigated the chemical foxing and in particular the iron oxidation to be able to understand the formation mechanism of foxing. Measurements were performed on ID26 at ESRF on three different kinds of samples: A) Samples prepared and aged at ICPL (Istituto Centrale per la Patologia del Libro)to simulate the foxing spotsB) Samples prepared at ESRF during the experiment to follow the foxing formation mechanism from the beginningC) historical samples to compare the results obtained from the artificially prepared samplesFirst interesting results were obtained by these measurements varying the starting iron solution [Fe(II) and Fe(III) solution were used to simulate the foxing], the solution concentration and the artificial aging process. The foxing mechanism seems to be strongly dependent from the local structure of cellulose. Moreover, these measurements gave us important indications to plan new experiments to understand in depth this complex phenomenon.INFMeeting 2004 – Genova, 8-10 giugno 2004.
Sodo, A., Bicchieri, M., Neisius, T. (2004). Applications of XAS to Cultural Heritage.
Applications of XAS to Cultural Heritage
SODO, ARMIDA;
2004-01-01
Abstract
X-rays Absorption Spectroscopy (XAS), for its features of high elemental selectivity, spatial resolution and non- destructivity, is a useful tool to study materials that form and decorate art object and to identify different degradation processes that can occur in works of art.In this study, it will be investigated a typical phenomenon of paper alteration called foxing, which appears as spots of variable dimensions generally colored from lemon yellow to dark-brown with sharp or irregular edges. Over the years, in fact, paper undergoes a series of alterations caused both by external and internal factors leading to cellulose degradation. This degradation is one of the greatest problems for the conservation of paper supports such as archival documents, books and artistic works. Degraded papers can show an evident fragility, a general yellowing and the formation of foxing spots that can, in some cases, not only damage the aesthetic of the object, but also compromise the readability of the text or the artistic works. The understanding of the different chemical processes underlying this degradation is of great importance to prevent further damage and to choose the appropriate restoration method. The foxing spots are generated by a complex mechanism based on the oxidation of iron or copper ions (chemical hypothesis) or on micro-organism based processes (microbiological hypothesis). By XAS we have investigated the chemical foxing and in particular the iron oxidation to be able to understand the formation mechanism of foxing. Measurements were performed on ID26 at ESRF on three different kinds of samples: A) Samples prepared and aged at ICPL (Istituto Centrale per la Patologia del Libro)to simulate the foxing spotsB) Samples prepared at ESRF during the experiment to follow the foxing formation mechanism from the beginningC) historical samples to compare the results obtained from the artificially prepared samplesFirst interesting results were obtained by these measurements varying the starting iron solution [Fe(II) and Fe(III) solution were used to simulate the foxing], the solution concentration and the artificial aging process. The foxing mechanism seems to be strongly dependent from the local structure of cellulose. Moreover, these measurements gave us important indications to plan new experiments to understand in depth this complex phenomenon.INFMeeting 2004 – Genova, 8-10 giugno 2004.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
