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The control of humidity between certain limits is essential to avoid the alteration of historical objects, such as unstable historical glasses. However, the usual limits can be altered due to the presence of volatile organic compounds. This work presents the results of the exposure of soda, potash, and mixed‐alkali silicate glasses to neutral and acidic (formic) atmospheres with ∼30%, ∼70%, and ∼100% relative humidity. The hygroscopic capacity of the glass was analyzed by gravimetry, and the surface alteration was evaluated by infrared spectroscopy, optical microscopy, and ion chromatography. In all glasses, the alteration begins with alkali ions' lixiviation followed by the silica network's hydrolytic attack. The results showed that soda and mixed‐alkali silicate glasses exhibit similar behavior, while the potash‐lime one experienced the fastest degradation due to its composition. Results also confirmed that high humidity increased the alteration rate causing a higher hygroscopicity and reactivity of glasses. Finally, acidic environments promoted the ion‐exchange reaction at high humidity, accelerating the lixiviation of alkaline ions and promoting the diffusion of water into the glass network. [ABSTRACT FROM AUTHOR]

The scientific research output of individuals and institutions is commonly evaluated by the number of publications in journals with high impact factor and their corresponding citations. However, the interdisciplinary character of journals reporting advances in conservation science favors their spread over different categories of the Journal Citation Report (JCR). Here we report an analysis of the evolution of the impact factor, the percentile, and the citations on the JCR indexed conservation journals over the last ten years. Our analysis shows that of the 57 conservation journals indexed in the JCR, only eight of them have an impact factor. These journals are distributed across different categories in the Science Citation Index (SCI) and Social Science Citation Index (SSCI), and these categories are sometimes not suitable and decrease their metric impact. This analysis was complemented by a worldwide survey of conservation professionals on their opinions about publishing in these journals. The survey showed two different perspectives about conservation science journals in relation to the background and work of the responders. Conservators and restorers prefer conservation journals with case studies; while researchers prefer high-impact journals, even if they lie outside of the conservation area, so the overall impact factor of conservation journals remains low (low JIF, low Q values). This dichotomy could be fixed with the creation of a new category for heritage science journals in JCR. [ABSTRACT FROM AUTHOR]

Stained glass restoration generally involves filling glass losses to maintain the coherence of the window and the new glasses used to fill the losses can be painted to chromatically reintegrate the stained glass panel. One of the most common painting materials on stained glass is grisaille, a paint made by mixing metal oxides with a ground lead glass. Grisailles usually have black and brown hues and are used for the creation of outlines as shadows in window glasses. Although several commercial companies sell many types of products to paint on glass, few of them present the necessary compatibility with the original materials that conservation materials must have. Debitus is one of the most renowned companies, and its grisailles are frequently used for chromatic reintegration in stained glass window restoration. Thus, the main objective of this study was to assess the long-term stability and durability of commercial Debitus grisailles. Two alteration tests were carried out, with samples placed in high humidity chambers and submerged in distilled water. The samples and degradation products were characterized by optical microscopy, µ-Raman spectroscopy, and colourimetry. In the immersion, the pH of the water was measured during the experiment, and the leached elements were analyzed at the end by inductively coupled plasma atomic emission spectroscopy. The results showed an alteration of the colour and the formation of degradation products, identified as sulphates. The solution pH was increased by the aqueous extraction of alkaline and alkaline-earth ions from the support glass of the samples. Despite these changes, it was possible to conclude that these commercial grisailles presented good durability and stability for use in conservation treatments. [ABSTRACT FROM AUTHOR]