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[EN] The following work is focused on the study of the suitability of the urea-aldehyde resin, commercially known as Laropal (R) A81, for consolidation treatments on deteriorated wood from panel paintings. The physicochemical properties of this resin, such as the low molecular weight, low viscosity in solution and, interestingly, the possibility to be dissolved in low-toxicity solvents, suggest that Laropal (R) A81 could penetrate well into the wood microstructure thus offering an alternative option to other resins which require the use of more harmful solvents. The behaviour of Laropal (R) A81 for the consolidation of deteriorated wood was compared to that of other two resins widely used as consolidants - Regalrez (R) 1126 and Paraloid (R) B72. Laropal (R) A81 was dissolved in Mostanol and in Dowanol PM, the Paraloid (R) B72 in butyl ethanoate and the Regalrez (R) in cyclohexane. ATR-FTIR was used for the assessment of resin retention and penetration depth in the wood, whereas FESEM images allowed us to evaluate the morphological changes undergone by the wood as a consequence of the application of the consolidation treatments. The changes in the gloss of the wood were also evaluated, which complemented the results obtained by the other two tests. According to the results obtained in this study, we argue that urea-aldehyde resin has good specificities (good retention and penetration depth) in order to be used as a consolidant for deteriorated wood in easel paintings.

The aim of this work was to compare the preferred chromatic composition for unfamiliar paintings with the original. Stimuli were images of paintings generated by rotating the color volume around the L* axis in CIELAB. The images were presented on a CRT. Four paintings were abstract from Amadeo de Souza-Cardoso, two had figurative elements from the same painter, two were abstract and two were figurative from other painters. In each trial a painting selected at random from the set was presented with its color volume rotated by angle selected at random. The task of the observer was to adjust the angle of the chromatic rotation for best subjective impression. Three groups of observers carried out the experiment: 50 without previous knowledge of the paintings, 8 experts in art but unfamiliar with the paintings tested and 6 experts in the paintings of Amadeo de Souza-Cardoso. It was found that the distribution of angles selected for data pooled across paintings for the non-specialist observers could be described by a Gaussian function centered at - 2 deg, i.e. close to the original colors of the paintings, and with a FWHM of 64 deg, just about 1.5 above the threshold to detect a chromatic change, FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the project PTDC/MHC-PCN/4731/2012, info:eu-repo/semantics/publishedVersion

The restoration of the cultural heritage with dramatic losses – whether they are the results of a natural processes or a human action – is a subject increasingly discussed between conservators and art historians nowadays. The approaches in formulating general guidelines involve many different aspects to be considered ranging from technical and sociological to philosophical and psychological points of view. Although considerable research has been devoted to architectural and archaeological heritage, rather less observation has been paid to recovery of visual arts. This study is related to the major recovery project of a 18th century oil painting on canvas depicting "Our Lady of the Rosary" which is celebrated as the patron saint of the parish community of Vrlika and its surroundings. During the Croatian War of Independence in 1992 the painting was taken off the main altar and vandalized. The central part of the composition, including almost the complete figures of Virgin Marry and the Child, was cut-out and taken away by the paramilitary units. This deliberate destruction by a human hand terminated a century long tradition of annual feasts in Vrlika in which the painting was publicly displayed and carried by the townsmen. Based on the cross referencing available visual materials ; a high resolution old black and white photograph and the low resolution coloured photograph, the computer colorization algorithm, and also relying on the non-invasive technical analyses of the original paint layer, a major reconstruction was carried out in 2017. This one-year project was initiated and sponsored by a group of Franciscans from Vrlika with the primary intent of re-establishing the feast of "Our Lady of the Rosary" and customs of her popular cult. In addition to details of technical execution and challenges related to this sort of intervention, a particular interest in the opposing views of the authenticity and the social value of the artwork is given. It can be concluded that the recovery of the artworks with dramatic losses is an extremely complex social phenomenon that is difficult to characterize by any general factor or through any general approach.