Overcoming Challenges in Street Art Murals Conservation: A Comparative Study on Cleaning Approach and Methodology

Chemical characterisation of artists' spray-paints: A diagnostic tool for urban art conservation

In this study the chemical characterisation of 24 commercial spray-paints in different colours as used in contemporary public murals, street art, and graffiti is presented. The analyses were focused on the identification of the binding media, pigments, and additives. In addition, four spray-paint samples were analysed in the form of bi-layered paint films to explore the possibility of determining the composition of multi-layered samples. The aim of the study was to provide a useful diagnostic tool for the conservation of spray-paints and the removal of overpaintings from both commissioned murals and any other form of cultural heritage. To achieve this goal, a multi-analytical approach was developed using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) for the identification of the main binder, pigments, and fillers/extenders, while Raman spectroscopy and Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS) were used as complementary tools for the determination of organic and inorganic pigments, and fillers. Five kinds of binders were detected in this work: (1) acrylic resins combined with nitrocellulose, (2) acrylic resins modified with styrene and combined with nitrocellulose, (3) alkyd resins modified with styrene and combined with nitrocellulose, (4) combined acrylic and alkyd resins modified with styrene and blended with nitrocellulose, and (5) combined polystyrene and acrylic resins. Also, a wide variety of organic pigments and inorganic components were detected.

Assessing the (In)Stability of Urban Art Paints: From Real Case Studies to Laboratory Investigations of Degradation Processes and Preservation Possibilities

Urban art as a shared expression of street art between artists, citizenship and municipalities has always had an important role in the social life and appearance of modern cities. However, the durability of urban and street artworks is susceptible to the degradation processes that the employed commercial paint formulations undergo once outdoors. These are complex mixtures of compounds, differently sensitive to environmental agents according to their chemical nature. Starting from the colorimetric analysis of murals created in 2010, 2011 and 2018 in Reggio Emilia, Italy, documenting their degradation already after a few months, this study aimed at understanding the stability of the most unstable paints used by the artists in these artworks. A multi-analytical approach evaluated the commercial products under the chemical point of view, after natural and accelerated ageing. Additionally, two manufactured anti-UV varnishes were evaluated for their possible use as coatings. The results pinpointed the weaknesses of the selected paints and highlighted how the application of an anti-UV coating might slightly affect the visual aspect of the artwork, though ensuring a greater resistance to the outdoor conditions due to their minor chemical sensitivity to environmental agents.

Protection of Urban Art Painting: A Laboratory Study

Urban art is a form of artistic visual expression and communication that is created in the street and generally in the public dimension of urban spaces. Often these kinds of artworks are in outdoor environments, and they usually suffer from atmospheric weathering and anthropic vandalism. Recently, several strategies have been used to limit or remove the effects of such vandalism. Currently, the use of quartz paints is growing among artists; such paints after setting are more porous and rough on the surface with respect to regular paints. The aim of the study is to assess the performance of anti-graffiti coatings on quartz artworks paints. Two anti-graffiti products were chosen, and their behaviors were assessed in the laboratory by means of contact angle measurement, water capillary test, colorimetric analysis, and optical and electron microscopy. Results showed good water repellence efficacy of the tested products, demonstrating that they are suitable for the protection of urban art, but at least two applications on the surface are needed to achieve good performance.