Evaluation of the use of Funori for consolidation of powdering paint layers in wall paintings

Abstract

Wall Painting Conservator-restorer in private practice, Lugano, SwitzerlandFunori is a polysaccharide-based adhesive extracted from seaweeds and is generally used in the conservation of easel paintings for the consolidation of matte paint. It is appreciated since it does not change the optical properties of the consolidated materials and its mechanical properties do not change with ageing. Because of these characteristics, this research focused on the evaluation of Funori as a suitable material for the consolidation of powdering paint layers in wall paintings. Tests were carried out where Funori was applied onto painted plaster replicas, which were then artificially aged and investigated in order to evaluate the material's behaviour according to the specific properties and conditions of wall paintings. The effectiveness of the consolidation was evaluated from the point of view of adhesive power, as well as the interactions of Funori with some physical properties of the consolidated painting, such as colour and water vapour permeability and, therefore, its resistance to accelerated ageing and biological colonization. In addition, the behaviour of Funori applied on plasters contaminated with soluble salts, a frequent condition in wall paintings, was also evaluated.

An investigation into adhesives to consolidate distemper paintings on canvas

“…Finally, Isinglass®, a refined grade of fish glue made from the dry swim bladders of the sturgeon fish, and Funori, a polysaccharide-based adhesive that is extracted from some red seaweeds species of Gloiopeltis genus (Swider and Smith 2005;Catenazzi 2016)…”

“…Thus, the samples were subjected to two relative humidity cycles to evaluate the efficacy of the adhesives in uncontrolled environments. The cycles were based on previous studies that investigate the same types of consolidation processes for matte paint (Catenazzi, 2016;Geiger and Michel, 2005). Conditions will be described in section 3.2.3.…”

Color changes in wall paintings under the influence of consolidation with synthetic polymers

“…15,16 Also, the latest practice and research in the field of wall paintings consolidation focus on nanolime as well as silicate preparations, natural remedies, or biodegradable polymers, which are safe not only for the paintings but also for human health and the environment. [17][18][19][20][21][22][23] In this study, we are focusing on researching color changes taking place in wall paintings as a result of their consolidation with the use of synthetic polymers and the ones resulting from the progress of degradation, with the aim of determining the actual impact of synthetic binders used as consolidants on paint layer properties.…”

In situ characterisation of readhesion treatments for ceiling paintings using unilateral NMR

“…Loss of adhesion is a common wall painting conservation problem [1]. Its remediation is complicated due to the paint layers forming the interface between the environment and the building.…”

“…It is favoured in conservation interventions due to its low surface tension, matte finish, solubility in water, and nontoxic properties [19] . It is also thermo-hygrally stable, optically stable, and not particularly susceptible to biological attack [1]. It was selected for trialling for four reasons: 1) it forms a relatively weak bond [20], allowing failure at the original fracture if re-exposed to stress 2) it forms a viscous solution at very low concentrations, reducing the amount of material added to the system and therefore limiting alterations in porosity and thermal-hygral behaviour of original material 3) the water carrier is highly polar and therefore does not disrupt previously applied resin Recent research [1] indicates high concentrations of some soluble salts may increase gelling and so hinder penetration of the funori into the substrate, although this did not discount its use in this case.…”