Multidisciplinary Studies on Canvas Nature of Paintings at IFIN-HH Romania

Radiocarbon dating of pictorial support is usually less used. It is accepted for paintings with the estimated age older than the Stradivarius limit (ca. 1600 - 1650 CE) as stated by A.J.T. Jull in 1997, and not as an authentication method. Considering this, a seventeenth century oil-based painting (Main Case Study) is reported. Based on the results obtained as terminus post quem , the painting cannot be attributed to the famous painter from the classical period, considered to be the author, according to the signature. Two other recently solved cases (Sample 1 and Sample 2) are briefly recorded and the information obtained was used for a more accurate interpretation of the Main Case Study. The multidisciplinary research aimed to put together, for the first time in the RoAMS Laboratory Romania, the information obtained through elemental analysis, ATR-FTIR, FT-Raman and XRF spectrometry. Radiocarbon dating process includes a comparative description of pictorial fragment pretreatments, of the textile fiber graphitization stage, and of AMS measurements used for determinations of isotopic ratio of carbon species, and general process parameter delta 13 C, of percent of Modern Carbon, and Conventional Radiocarbon Age, and of the Standard Deviations. The fragment of (Main Case Study) was first investigated using both FT-Raman and ATR-FTIR spectrometry. The spectra obtained reveal that the painting surface was covered with a thick layer of linseed oil, which hinders a complete analysis of the pigments through FT-Raman and ATR-FTIR spectrometry. However, the white pigment (lead white) and primer (calcium carbonate) were successfully identified. The findings from ATR-FTIR and FT-Raman spectra provide reliable information about the contaminants, information that is further used to select the most appropriate dating strategy. Before the AMS measurements, the cleaned textile fibers were investigated by elemental analysis, ATR-FTIR and micro-DRIFT spectrometry. The data obtained were compared with known natural and artificial textile fibers. The results reveal an almost complete decontamination, which additionally underlines the assumption that the textile support used exhibits a synthetic nature. Most likely, the canvas was made of synthetic nylon 6.6 fibers on a texture close to sailboat, used for sailing in the mid-twentieth century. The findings were finally confirmed by radiocarbon dating. 14 C/ 12 C isotopic ratios were close to RoAMS Laboratory background level, certifying a raw material from fossil deposits. The other fragments of canvas, those from recently solved cases (Sample 1 and Sample 2) are supposed to belong to the first part of the seventeenth, or to nineteenth / twentieth centuries (where the presumptions were made, and where the final results are placed, for Main Case Study). The compara tive data reveal different particularities observed for each situation, offering pro and con arguments in determining the fibers age(s). The information provided by radiocarbon dating, elemental analysis and XRF spectrometry is in good agreement and demonstrates that it is unlikely that the authors designated for each case were those who created the paintings. The XRF spectrometry investigation highlighted the use of primers or pigments that generally appeared in the painting technique after the date when the painting creation was estimated. (c) 2021 Elsevier Masson SAS. All rights reserved.

Automated summary

Radiocarbon dating of pictorial support is not commonly used, with results indicating that the seventeenth century oil-based painting may not be attributed to the famous classical period painter as previously assumed. Additional multidisciplinary research on recently solved cases provided more accurate interpretation, with elemental analysis and XRF spectrometry supporting the unlikelihood of attributing paintings to their designated authors.