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Amsterdam-Zuidoost, Netherlands

Pozzi F.,School of the Art Institute of Chicago | Van Den Berg K.J.,Cultural Heritage Agency of the Netherlands | Fiedler I.,School of the Art Institute of Chicago | Casadio F.,School of the Art Institute of Chicago
Journal of Raman Spectroscopy | Year: 2014

The Art Institute of Chicago (AIC) owns one of the largest and very finest collections of 19th century French Impressionist and Post-Impressionist paintings in the world. While the palette of the Impressionists has been extensively characterized for what concerns both traditional and innovative inorganic pigments, to date, the identification of the red organic lakes - widely used for their intense, brilliant color - has posed an analytical challenge. In this work, firstly, surface-enhanced Raman spectroscopy has been applied to the analysis of red lake paint reconstructions prepared according to 19th century historical recipes. Results demonstrated that dye identification can be successfully accomplished on Lee-Meisel colloids after hydrolysis with hydrofluoric acid, even when inorganic pigments, extenders, ground materials or binding media are associated with the red lake in the sample analyzed. Subsequently, the same protocol was used to examine samples from Manet, Pissarro, Renoir, Monet and Gauguin paintings in the AIC collection. Results showed the predominant use of madder and cochineal lakes, sometimes in combination, thus greatly enhancing our knowledge of the Impressionist usage of different types of red lakes. Copyright © 2014 John Wiley & Sons, Ltd.

Pereira C.,New University of Lisbon | Busani T.,New University of Lisbon | Branco L.C.,New University of Lisbon | Joosten I.,Cultural Heritage Agency of the Netherlands | Anca Sandu I.C.,New University of Lisbon
Microscopy and Microanalysis | Year: 2013

This work establishes a multiscale and multitechnique nondestructive approach as valid methodology for monitoring surface properties and evaluating the effectiveness of enzymatic removal of varnishes from paintings/polychrome artefacts. Mock-up samples (documented reconstructions of oil, tempera, and gilded layers on canvas and wooden supports) were covered with different proteinaceous varnishes (egg white, animal and fish glue, casein) and then characterized before and after the removal of these coatings with enzyme-based solutions. The varnish was cleaned in several steps (two dry swabs and two wet swabs) with a clearance step for removing the residues from proteinaceous varnish or from enzyme solution. Microscopy [stereomicroscopy (SM), optical microscopy (OM), atomic force microscopy (AFM), and scanning electron microscopy (SEM)] and colorimetric (CIE L*a*b* system) techniques were used for characterization of the reconstruction surfaces at different scales (macro-scale by SM and OM; micro-scale by SEM and nano-scale by AFM). These techniques were also used to monitor the cleaning treatment. Although results presented in this work were obtained for the specific treatment of enzyme removal, the methodology could be extended to other types of materials and cleaning. Further experiments on real works of art are needed for a complete validation of the methodology. Copyright © 2013 Microscopy Society of America.

Brokerhof A.W.,Cultural Heritage Agency of the Netherlands | Bulow A.E.,British Museum
Journal of the Institute of Conservation | Year: 2016

Over the past two decades a number of heritage institutions have conducted different forms of risk assessments. Despite the generally agreed profound changes such assessments make to an organization's approach to the care of its collection, there remains a general apprehension concerning the significant effort required to execute such an assessment. This paper describes the development of the QuiskScan, a quick risk scan, which yields an overview over a collection, its values and vulnerabilities with comparatively little effort. The QuiskScan uses a matrix-based approach to map value and vulnerability to the agents of deterioration for different collection units to highlight where significant losses to the collection might occur. Like other risk assessment approaches the QuiskScan involves expert input from across the organization thus helping to create a shared insight into the collection, and an institutional awareness of risks. The method should be regarded as a tool that fits in between relying on best practice and conducting a comprehensive risk assessment.

van Geel B.,University of Amsterdam | Brinkkemper O.,Cultural Heritage Agency of the Netherlands | Weeda E.J.,Veerallee 28 | Sevink J.,University of Amsterdam
Geologie en Mijnbouw/Netherlands Journal of Geosciences | Year: 2016

We studied a Holocene peat fill of a small depression in Pleistocene coversand, in the western border zone of Het Gooi, to assess the early local and regional vegetation history in relation to sea-level rise, soil development and potential human impact. In the fourth millenium BC, a podzol which had formed in the depression became stagnative, leading to the development of a moorland pool. The local vegetation changed from dry heathland, through an amphibic vegetation type with, among others, Littorella uniflora and Lycopodiella inundata, to a permanently moist Sphagnum-dominated vegetation. The existence of moorland pools and the development of such habitats into Sphagnum-dominated vegetation are known from Late-Holocene anthropogenic, more or less open landscapes that were formed on a podzolising sandy soil under ericaceous vegetation. However, the recorded vegetation succession did not show any recognisable local human impact and therefore is attributed to natural succession. In the period concerned, sea level was still about 4 m below the land surface in the depression, implying that water logging occurred independent from a rise in sea level and associated groundwater level. It took until the Late Middle Ages before such rise led to significant water logging and peat growth in this border zone, but the mean groundwater level never reached to above NAP (Dutch Ordnance Datum). Copyright © Netherlands Journal of Geosciences Foundation 2016

van Driel B.A.,Rijksmuseum Amsterdam | van Driel B.A.,Cultural Heritage Agency of the Netherlands | van Driel B.A.,Technical University of Delft | Kooyman P.J.,Technical University of Delft | And 4 more authors.
Microchemical Journal | Year: 2016

Titanium dioxide is the most abundantly used white pigment of the 20th century. The pigment is still in use, both in the production of contemporary art and for the conservation of older artwork as a retouching pigment. Unfortunately, next to its positive characteristics, the pigment has one major potential drawback: its photocatalytic activity that can cause degradation of artworks in which it is used. In this paper, we report on a new method to test the photocatalytic activity of different quality grades of titanium dioxide white pigments. This can be done quantitatively in a chemical lab or qualitatively in a quick and easy way, in a museum or artists' studio, with limited use of lab equipment. The photocatalytic degradation of an organic dye, acid blue 9, in an aqueous solution containing titanium dioxide, is followed over time by means of UV-Vis spectrophotometry. Dye solutions containing pigments with high photocatalytic activity lose their color within several hours of UVA exposure. On the other hand, dye solutions containing UV-stable titanium dioxide do not degrade within 24 h of UVA exposure. Insight in the photocatalytic activity of titanium white pigments, which can be obtained with this novel test, is of great importance for preventive conservation of modern art. © 2015 The Authors.

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