COMBINED C-14 ANALYSIS OF CANVAS AND ORGANIC BINDER FOR DATING A PAINTING

The use of accelerator mass spectrometry (AMS) for age determinations of paintings is growing due to decreasing sample size requirements. However, as only the support material is usually dated, the validity of the results may be questioned. This work describes a novel sampling and preparation technique for dating the natural organic binder using radiocarbon (C-14) AMS. In the particular case of oil paintings, the natural oil used has a high probability of being representative of the time of creation, hereby circumventing the problem of the originality of the support material. A multi-technique approach was developed for a detailed characterization of all paint components to identify the binder type as well as pigments and additives present in the sample. The technique was showcased on a painting of the 20th century. The results by C-14 AMS dating show that both the canvas and binding medium predate the signed date by 4-5 yr. This could be the time span for keeping painting material in the atelier. The method developed provides, especially given the low amounts of material needed for analysis, a superior precision and accuracy in dating and has potential to become a standard method for oil painting dating

Bildgebende Untersuchungsverfahren im Infrarotbereich: neue Entwicklungen und Anwendungsbeispiele

Bildgebende Untersuchungsverfahren, die den infraroten Wellenlängenbereich der elektromagnetischen Strahlung nutzen, haben für die Erforschung, die Konservierung und die Restaurierung von Kunst- und Kulturgut eine besondere Bedeutung. So können mit Hilfe der (Mikro-) Infrarot-Reflektografie, der Infrarot-Transmission und der Lock-In Thermografie unter der Oberfläche verborgene Strukturen und Schadensphänomene sichtbar gemacht werden, die dem menschlichen Auge sonst verborgen sind. Im Vortrag werden neue technische Entwicklungen, aktuelle Anwendungsbeispiele und mögliche Einsatzgebiete in der kunsttechnologischen Forschung vorgestellt

Acuros® CQD® SWIR Camera Applications Note - High Resolution Infrared Reflectography of Painting Underdrawings

Infrared reflectography of paintings is used to make underlying layers clearly visible in contrast. IR radiation penetrates the upper layers of the painting and is reflected by the primer. The underdrawing, which is made with carbonaceous colorants on the primer, absorbs IR radiation and shows a strong contrast. The 2 MP sensor of the camera in combination with a lens with a short minimum working distance allows the realization of a very high resolution, which is important for the possibility to evaluate the underdrawing. The effective achievable resolution is therefore dependent on both components, sensor and lens

Microscale radiocarbon dating of paintings

In this paper, radiocarbon dating of paintings using minimal sample sizes has been investigated, in an effort to address the problem of limited access to sample material in paintings. 14C analyses were conducted on signed and dated paintings from two Swiss artists of the twentieth century. The selected paintings dated from the 1930s and 1960s, provided the opportunity to evaluate the dating accuracy on paintings realized before and after 1950 AD when the 14C bomb peak was created, as a result of the nuclear tests conducted in the 1950/1960s. The work focused on the one hand on minimizing the size of the canvas sample required for accelerator mass spectrometer radiocarbon measurement on the gas ion source of the MICADAS and, on the other hand, on testing the possibility of dating the organic binder of the paint. Following careful characterization of the paint composition by X-ray fluorescence spectroscopy, Fourier transformed infrared spectroscopy, and Raman spectroscopy, paints containing no other carbon source than the natural organic binder were identified and dated

Dual isotope system analysis of lead white in artworks

Isotopic studies are gaining much interest in heritage science, as they can provide insight into a material's age and provenance. Radiocarbon (14C) dating affords a time frame for the materials being studied, thus providing a historical context, whereas the specific pattern of lead isotope ratios may be used to set geographical constraints on the source of the original materials. Both methods require invasive sampling from the object, and henceforth limits their respective application. With the focus on lead white paint (2PbCO3·Pb(OH)2), in this study we extract the time of production of the pigment from the carbonate anion by radiocarbon dating while its origin is traced by lead isotope analysis on the cation. The methodology was applied to 12 British and 8 Swiss paintings from the 18th to 20th century, with known dates and provenance. The 14C analysis of the lead white in combination with the organic binder and canvas alone places all objects between the 17th and 20th centuries, which is in agreement with their signed date, wheras the lead isotope analysis of all samples are consistent with lead ores from European deposits. In most of the cases the combined results are consistent with the art historical data and prove that isotope analysis is intrinsic to the object. This feasibility study conducted on paintings of known age demonstrates the possibility to maximize the information output from lead white paint, thus increasing the benefits of a single sampling

Combined 14

The use of accelerator mass spectrometry (AMS) for age determinations of paintings is growing due to decreasing sample size requirements. However, as only the support material is usually dated, the validity of the results may be questioned. This work describes a novel sampling and preparation technique for dating the natural organic binder using radiocarbon (C-14) AMS. In the particular case of oil paintings, the natural oil used has a high probability of being representative of the time of creation, hereby circumventing the problem of the originality of the support material. A multi-technique approach was developed for a detailed characterization of all paint components to identify the binder type as well as pigments and additives present in the sample. The technique was showcased on a painting of the 20th century. The results by C-14 AMS dating show that both the canvas and binding medium predate the signed date by 4-5 yr. This could be the time span for keeping painting material in the atelier. The method developed provides, especially given the low amounts of material needed for analysis, a superior precision and accuracy in dating and has potential to become a standard method for oil painting dating

Age and Provenance Analysis from Micrograms of Artwork Pigments

ISSN:0009-429

Selective dating of paint components Radiocarbon dating of lead white pigment

This study was funded by an ETH-grant (ETH-21 15-1).Lead white is a man-made white pigment commonly used in works of art. In this study, the possibility of radiocarbon dating lead white pigments alone and in oil paints was explored using well-dated lead white pigments and paints. Resulting 14C ages on lead white pigments produced following the traditional stack process, where carbonate groups results from the incorporation of CO2 originating from fermentation, matched the production years, while radiocarbon dating of lead white made using other industrial processes indicate that 14C depleted CO2 was used in their production. The method was applied to two case studies, where lead carbonate samples were dated in two oil paintings, one Baroque and one from the 20th century. We hereby show that the lead white pigment can be dated by 14C and used as proxy for the time of creation of an artwork. Additionally, a two-step method was developed to allow 14C analysis of both the lead white pigment and oil binder from the same sample. A single lead white paint sample can yield two distinct radiocarbon ages, one from the carbonate and one from the natural organic binder. This study thus proposes new strategies for 14C dating of artworks.publishersversionpublishe

The Ins and Outs of 14C Dating Lead White Paint for Artworks Application

Lead white is known as one of the oldest pigments in art and can be used as a dating material. Upon production following the Stack process, the 14C isotope of atmospheric carbon dioxide is fixed in the carbonate, and its radiocarbon dating can be used as a proxy for the age of a painting. The previously reported carbonate hydrolysis protocol reaches its limitation when confronted with samples presenting a mixture of carbonates, such as lead carbonate (cerussite or hydrocerussite), calcium carbonate (calcite), and/or calcium magnesium carbonate (dolomite). Thermogravimetric analyses indicate that decomposition of lead carbonate can be achieved at 350 °C in TGA diagrams, as other mineral carbonates only decompose to carbon dioxide at temperatures above 700 °C. Thus, a thermal approach is proposed to separate the various carbonates and isolate the specific 14C signature to the lead carbonate. In practice, however, discrepancies between the measured radiocarbon ages and expected ages were observed. FTIR analyses pointed to the formation of metal carboxylates, an indicator that the organic binder is not inert and plays a role in the dating strategy. Upon drying, oxidation and hydrolysis take place leading to the formation of free fatty acids, which in turn interact with the different carbonates upon heating. Their removal was achieved by introduction of a solvent extraction step prior to the thermal treatment, which was confirmed by GC-MS analyses, and thus, the collected carbon dioxide at 350 °C results can be assigned correctly to the decomposition of the lead white pigment. The proposed procedure was furthermore verified on mixed carbonate-bearing paint samples collected from a Baroque oil painting.ISSN:1520-6882ISSN:0003-270