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Papers by Gabriëlle Beentjes
Journal of Paper Conservation, 2020
ABSTRACT In 1994–1995 the same editions of printed books were treated by four mass deacidificatio... more ABSTRACT In 1994–1995 the same editions of printed books were treated by four mass deacidification methods: diethyl zinc, Wei T'o, Battelle, and Bookkeeper. Forty one titles from 1832 to 1991 were sampled from a dissertation collection and four sets sent to mass deacidification plants, while one set was untreated. In 2019, 155 paper samples were analysed for alkaline reserve and pH (cold extract) to compare the performance of treated books with untreated ones. Twenty samples were analysed for degree of polymerization by viscosity average. User experience has also been tested, in 1996 and in 2019. Results showed higher pH and AR for treated books compared to those untreated, and a greater experienced effect for the untreated compared to the treated today. For pH and AR there were differentiations between the deacidification methods, while the results for DP showed greater complexity, pointing to the need for on-going further studies of mass deacidified books.
Foreword 1. Formulation of objective and questions 2. Introduction 2.1 The history of office copi... more Foreword 1. Formulation of objective and questions 2. Introduction 2.1 The history of office copies 2.2 Types of damage 2.3 Conservation of office copies 2.4 Pressed letter book (1780-1958) 2.5 Carbon (1850-1990) 2.6 Stencil (1871-1980) 2.7 Hectograph and spirit duplication (1878-1975) 2.8 Diazo/Océ (1930-1970) 3. Design and implementation of the research 3.1 Sampling 3.2 Identification of copies 3.3 Training of research staff 3.4 Sampling 3.5 Sampling of the selected samples 3.6 Chemical analysis 3.7 Light fading 4. Results 4.1 Research question 1 4.2 Research question 2 4.3 Research question 3 4.4 Research question 4 5. Conclusion and discussion 6. Recommendations and suggestions for further research
Studies in Conservation, 2020
This paper proposes the use of simulation modelling to explore the effect of conservation strateg... more This paper proposes the use of simulation modelling to explore the effect of conservation strategies on the preservation of paper collections. Agent-based simulation was chosen as the simulation approach in order to capture the individual characteristics of the collections, their size, and the values of pH and degree of polymerisation (DP) for individual items. This approach enabled the simulation of the chemical degradation of different types of collections during their lifetime and under different preservation scenarios. We conducted a series of computational experiments on three types of collections, acidic, modern, and mixed, to explore the effect of slightly lowering the temperature and relative humidity in the repositories, the deacidification of part of the collection at different rates, and the delay in making the decision to start a deacidification treatment. The results indicated that a small change, lowering the storage conditions from 18°C to 16°C and from 50% to 40% RH, can protect up to 30% of the collection from reaching the critical DP of 300 within a time horizon of 500 years. On the other hand, to obtain similar results through deacidification, 45% of the mixed collection and 70% of the acidic collection should be deacidified within a period of 100 years. The experiments also indicated that better results are obtained when the priorities for deacidification are acidic records with a pH value below 5. This study shows that modelling the heterogeneity of the collections can support preservation management, particularly if the concern is not the preservation of a part of the collection but the collection as a whole.
Restaurator, 2011
Abstract Low-oxygen technology – ZerOx technology, offers new opportunities for museums, librarie... more Abstract Low-oxygen technology – ZerOx technology, offers new opportunities for museums, libraries and archives in protecting, preserving and treatment of biological infested objects. The ZerOx technology can be applied in any of the following areas: fire prevention, through permanent oxygen reduction; conservation, through active climate control of rooms or anoxic show cases; treatment of infested objects with the advantage of avoiding their contamination with chemicals. The contribution provides an overview of the working principle, the technology behind it, application possibilities, limitations and case studies. Zusammenfassung Die Low-Oxygen Technologie, die so genannte ZerOx-Technologie, eröffnet neue Möglichkeiten für Museen, Bibliotheken und Archive, für Schutz, Erhaltung und Behandlung biologisch geschädigter Objekte. Die Technologie kann in mehreren Bereichen angewendet werden: dem Brandschutz durch permanente Reduktion des Sauerstoffgehalts, der Erhaltung empfindlicher Materialien durch Kontrolle des atmosphärischen Sauerstoffs bzw. durch sauerstoffarme Atmosphäre in Vitrinen und schließlich der Desinfektion von durch Organismen befallenen Objekten mit dem Vorteil, dass ihre Kontamination mit Chemikalien vermieden werden kann. Der Beitrag gibt einen Überblick über die Prinzipien der Low-Oxygen Technologie. Die Möglichkeiten und Grenzen von deren Anwendung werden anhand von Fallbeispielen dargestellt. Résumé La technologie Low-Oxygen, appelée Technologie ZerOx, offre de nouvelles opportunités aux musées, aux bibliothèques et aux archives pour la protection, la conservation et le traitement de documents historiques biologiquement endommagés. Cette technologie peut être appliquée dans plusieurs domaines: dans la protection contre l'incendie grâce à la réduction permanente de l'oxygène, dans la conservation de matériaux sensibles à l'aide d'un contrôle de l'oxygène contenu dans l'atmosphère ainsi que par une atmosphère pauvre en oxygène dans les vitrines, et finalement grâce à une désinfection des objets ayant été infectés par des micro-organismes, ce qui présente comme avantage qu'une contamination par produits chimiques soit évitée. Cet article donne un aperçu sur les principes de fonctionnement de la technologie Low-Oxygen. Les possibilités et les limites de son application seront exposées à l'aide d'études de cas.
Cr Interdisciplinair Vakblad Voor Conservering En Restauratie, 2000
This article describes the treatment of a work by the Dutch artist Karel Appel, which dates from ... more This article describes the treatment of a work by the Dutch artist Karel Appel, which dates from 1949 and was made with gouache and crayon. The crayon has started to detach itself from the layer of gouache in several places and is also turning into powder. An interesting phenomenon is the forming of a white fur on the inside of the glass in the frame. Research shows that this consists of free fatty acids, paraffin and sodium stearate. The free fatty acids and the paraffin have evaporated from the crayon; the sodium stearate is a product of the stearine acide from the oil and sodium ions from the glass. Consolidation was achieved by using an ultrasonic mister and paintbrush in a climate chamber. The high level of moisture of the object in the climate chamber provided a good capillary activity and drenching with the consolidator (method a-4-c from the firm of Caldic). After treatment the damaged light blue areas turned out to have become dark blue, possible as a result of returning a binding agent to the composition of the crayon.
Journal of Infrared, Millimeter, and Terahertz Waves
This study aims to objectively inform curators when terahertz time-domain (TD) imaging set in ref... more This study aims to objectively inform curators when terahertz time-domain (TD) imaging set in reflection mode is likely to give well-contrasted images of inscriptions in a complex archival document and is a useful non-invasive alternative to current digitisation processes. To this end, the dispersive refractive indices and absorption coefficients from various archival materials are assessed and their influence on contrast in terahertz images from historical documents is explored. Sepia ink and inks produced with bistre or verdigris mixed with a solution of Arabic gum or rabbit skin glue are unlikely to lead to well-contrasted images. However, dispersions of bone black, ivory black, iron gall ink, malachite, lapis lazuli, minium and vermilion are likely to lead to well-contrasted images. Inscriptions written with lamp black, carbon black and graphite give the best imaging results. The characteristic spectral signatures from iron gall ink, minium and vermilion pellets between 5 and 100 cm −1 relate to a ringing effect at late collection times in TD waveforms transmitted through these pellets. The same ringing effect can be probed in waveforms reflected from iron gall, minium and vermilion ink deposits at the surface of a document. Since TD waveforms collected for each scanning pixel can be Fourier
Journal of Paper Conservation, 2020
ABSTRACT In 1994–1995 the same editions of printed books were treated by four mass deacidificatio... more ABSTRACT In 1994–1995 the same editions of printed books were treated by four mass deacidification methods: diethyl zinc, Wei T'o, Battelle, and Bookkeeper. Forty one titles from 1832 to 1991 were sampled from a dissertation collection and four sets sent to mass deacidification plants, while one set was untreated. In 2019, 155 paper samples were analysed for alkaline reserve and pH (cold extract) to compare the performance of treated books with untreated ones. Twenty samples were analysed for degree of polymerization by viscosity average. User experience has also been tested, in 1996 and in 2019. Results showed higher pH and AR for treated books compared to those untreated, and a greater experienced effect for the untreated compared to the treated today. For pH and AR there were differentiations between the deacidification methods, while the results for DP showed greater complexity, pointing to the need for on-going further studies of mass deacidified books.
Foreword 1. Formulation of objective and questions 2. Introduction 2.1 The history of office copi... more Foreword 1. Formulation of objective and questions 2. Introduction 2.1 The history of office copies 2.2 Types of damage 2.3 Conservation of office copies 2.4 Pressed letter book (1780-1958) 2.5 Carbon (1850-1990) 2.6 Stencil (1871-1980) 2.7 Hectograph and spirit duplication (1878-1975) 2.8 Diazo/Océ (1930-1970) 3. Design and implementation of the research 3.1 Sampling 3.2 Identification of copies 3.3 Training of research staff 3.4 Sampling 3.5 Sampling of the selected samples 3.6 Chemical analysis 3.7 Light fading 4. Results 4.1 Research question 1 4.2 Research question 2 4.3 Research question 3 4.4 Research question 4 5. Conclusion and discussion 6. Recommendations and suggestions for further research
Studies in Conservation, 2020
This paper proposes the use of simulation modelling to explore the effect of conservation strateg... more This paper proposes the use of simulation modelling to explore the effect of conservation strategies on the preservation of paper collections. Agent-based simulation was chosen as the simulation approach in order to capture the individual characteristics of the collections, their size, and the values of pH and degree of polymerisation (DP) for individual items. This approach enabled the simulation of the chemical degradation of different types of collections during their lifetime and under different preservation scenarios. We conducted a series of computational experiments on three types of collections, acidic, modern, and mixed, to explore the effect of slightly lowering the temperature and relative humidity in the repositories, the deacidification of part of the collection at different rates, and the delay in making the decision to start a deacidification treatment. The results indicated that a small change, lowering the storage conditions from 18°C to 16°C and from 50% to 40% RH, can protect up to 30% of the collection from reaching the critical DP of 300 within a time horizon of 500 years. On the other hand, to obtain similar results through deacidification, 45% of the mixed collection and 70% of the acidic collection should be deacidified within a period of 100 years. The experiments also indicated that better results are obtained when the priorities for deacidification are acidic records with a pH value below 5. This study shows that modelling the heterogeneity of the collections can support preservation management, particularly if the concern is not the preservation of a part of the collection but the collection as a whole.
Restaurator, 2011
Abstract Low-oxygen technology – ZerOx technology, offers new opportunities for museums, librarie... more Abstract Low-oxygen technology – ZerOx technology, offers new opportunities for museums, libraries and archives in protecting, preserving and treatment of biological infested objects. The ZerOx technology can be applied in any of the following areas: fire prevention, through permanent oxygen reduction; conservation, through active climate control of rooms or anoxic show cases; treatment of infested objects with the advantage of avoiding their contamination with chemicals. The contribution provides an overview of the working principle, the technology behind it, application possibilities, limitations and case studies. Zusammenfassung Die Low-Oxygen Technologie, die so genannte ZerOx-Technologie, eröffnet neue Möglichkeiten für Museen, Bibliotheken und Archive, für Schutz, Erhaltung und Behandlung biologisch geschädigter Objekte. Die Technologie kann in mehreren Bereichen angewendet werden: dem Brandschutz durch permanente Reduktion des Sauerstoffgehalts, der Erhaltung empfindlicher Materialien durch Kontrolle des atmosphärischen Sauerstoffs bzw. durch sauerstoffarme Atmosphäre in Vitrinen und schließlich der Desinfektion von durch Organismen befallenen Objekten mit dem Vorteil, dass ihre Kontamination mit Chemikalien vermieden werden kann. Der Beitrag gibt einen Überblick über die Prinzipien der Low-Oxygen Technologie. Die Möglichkeiten und Grenzen von deren Anwendung werden anhand von Fallbeispielen dargestellt. Résumé La technologie Low-Oxygen, appelée Technologie ZerOx, offre de nouvelles opportunités aux musées, aux bibliothèques et aux archives pour la protection, la conservation et le traitement de documents historiques biologiquement endommagés. Cette technologie peut être appliquée dans plusieurs domaines: dans la protection contre l'incendie grâce à la réduction permanente de l'oxygène, dans la conservation de matériaux sensibles à l'aide d'un contrôle de l'oxygène contenu dans l'atmosphère ainsi que par une atmosphère pauvre en oxygène dans les vitrines, et finalement grâce à une désinfection des objets ayant été infectés par des micro-organismes, ce qui présente comme avantage qu'une contamination par produits chimiques soit évitée. Cet article donne un aperçu sur les principes de fonctionnement de la technologie Low-Oxygen. Les possibilités et les limites de son application seront exposées à l'aide d'études de cas.
Cr Interdisciplinair Vakblad Voor Conservering En Restauratie, 2000
This article describes the treatment of a work by the Dutch artist Karel Appel, which dates from ... more This article describes the treatment of a work by the Dutch artist Karel Appel, which dates from 1949 and was made with gouache and crayon. The crayon has started to detach itself from the layer of gouache in several places and is also turning into powder. An interesting phenomenon is the forming of a white fur on the inside of the glass in the frame. Research shows that this consists of free fatty acids, paraffin and sodium stearate. The free fatty acids and the paraffin have evaporated from the crayon; the sodium stearate is a product of the stearine acide from the oil and sodium ions from the glass. Consolidation was achieved by using an ultrasonic mister and paintbrush in a climate chamber. The high level of moisture of the object in the climate chamber provided a good capillary activity and drenching with the consolidator (method a-4-c from the firm of Caldic). After treatment the damaged light blue areas turned out to have become dark blue, possible as a result of returning a binding agent to the composition of the crayon.
Journal of Infrared, Millimeter, and Terahertz Waves
This study aims to objectively inform curators when terahertz time-domain (TD) imaging set in ref... more This study aims to objectively inform curators when terahertz time-domain (TD) imaging set in reflection mode is likely to give well-contrasted images of inscriptions in a complex archival document and is a useful non-invasive alternative to current digitisation processes. To this end, the dispersive refractive indices and absorption coefficients from various archival materials are assessed and their influence on contrast in terahertz images from historical documents is explored. Sepia ink and inks produced with bistre or verdigris mixed with a solution of Arabic gum or rabbit skin glue are unlikely to lead to well-contrasted images. However, dispersions of bone black, ivory black, iron gall ink, malachite, lapis lazuli, minium and vermilion are likely to lead to well-contrasted images. Inscriptions written with lamp black, carbon black and graphite give the best imaging results. The characteristic spectral signatures from iron gall ink, minium and vermilion pellets between 5 and 100 cm −1 relate to a ringing effect at late collection times in TD waveforms transmitted through these pellets. The same ringing effect can be probed in waveforms reflected from iron gall, minium and vermilion ink deposits at the surface of a document. Since TD waveforms collected for each scanning pixel can be Fourier