Nanocellulose has been recently proposed as a novel consolidant for historical papers. Its use for painting canvas consolidation, however, remains unexplored. Here, we show for the first time how different nanocelluloses, namely mechanically isolated cellulose nanofibrils (CNF), carboxymethylated cellulose nanofibrils (CCNF) and cellulose nanocrystals (CNC), act as a bio-based alternative to synthetic resins and other conventional canvas consolidants. Importantly, we demonstrate that compared to some traditional consolidants, all tested nanocelluloses provided reinforcement in the adequate elongation regime. CCNF showed the best consolidation per added weight; however, it had to be handled at very low solids content compared to other nanocelluloses, exposing canvases to larger water volumes. CNC reinforced the least per added weight but could be used in more concentrated suspensions, giving the strongest consolidation after an equivalent number of coatings. CNF performed between CNC and CCNF. All nanocelluloses showed better consolidation than lining with synthetic adhesive (Beva 371) and linen canvas in the elongation region of interest.

During conservation treatment, consolidants and deacidifying agents can be added to the canvas of a painting to mechanically stabilise it and counteract the acidity that promotes degradation. In this study, new stabilising consolidants and deacidifying agents based on different nanoparticles (silica, calcium carbonate, magnesium oxide, cellulose nanofibrils and cellulose nanocrystals) were tested in comparison to traditionally used products. These products were applied onto different types of canvasses, and colour, gloss and pH changes were analysed. Conservators' subjective perceptions on the ease of application and the final visual results of the products were also assessed. Specifically, conservators were asked to examine the drying time and the ease of use of the products, as well as any changes in stiffness, darkening or whitening caused by the products on the canvasses. The best products were the ones based on calcium carbonate, magnesium oxide and cellulose nanocrystals. Cellulose nanofibrils are also promising consolidants because they are highly compatible with the chemical nature of painting canvasses.

This work presents the results of archaeobotanical examinations of fragments of monumental terracruda sculptures from the Buddhist sites of Tepe Narenj and Qol-e-tut (Kabul, Afghanistan—5th to eleventh centuries CE). The results indicate that different plants and parts of plants were intentionally added to the clay mixtures. In particular, we identified an extensive presence of bast fibres, which were not evidenced by macroscopic examinations and previous analyses. Among the fibres, we highlight the presence of ramie/nettle, whose use has been identified for the first time in this type of artworks. The determination of these herbaceous additives offer a new perspective for studying the manufacturing technique, as well as an anchor point to follow this tradition along the Silk Roads. It also provides relevant information that should be taken into account in the design of conservative interventions adapted to the specific nature of this heritage.

This study provides a detailed understanding of the heat fluxes and temperatures that take place in the channel between the inner face of an exterior wall and the back of a painted wood panel hung on it. This is performed by means of a numerical simulation with a 2 dimensional CFD software. Distributions of temperatures, heat fluxes, and other parameters are quantified for 56 cases where the classical equations-Raithby-Hollands and similar-cannot be applied as these require vertical isothermal plates or isofluxes. Studied scenarios include different panel heights, channel widths, and room heights. Combining these data with outside temperature (− 3 °C) and heating air supply temperature (20 °C), to provide a nearly constant 19.6 °C in the room except in the channel between panel and wall, and with two values of specific humidity in the room, we provide for every studied case, advised distances, for these conditions, between the panel and the wall.

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