Characterization Of Spray Paints Used In Street Art Graffiti By A Non-Destructive Multi-Analytical Approach

Often associated with acts of vandalism, graffiti can also be identified with the so-called street art movement. Moreover, in the historical context of visual arts from the 20th and 21st century, graffiti spray paints feature among the materials employed in the work of representative artists such as Lucio Fontana, Richard Hamilton, Yves Klein, or David Alfaro Siqueiros. In this study, a large number of artist spray paints were analyzed by means of X-Ray Fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), spectrophotometry, and Hyperspectral Imaging (HSI). The aim of the study was to provide a chemical characterization of the main organic and inorganic components present within the spray paint formulations by means of a complementary non-destructive approach. Titanium white, zinc white, bismuth vanadate yellow, ultramarine, strontium sulfide, iron, and copper oxides, along a series of pigments of the azo, phthalocyanine, and quinacridone classes could be identified. High amounts of barium sulfate as well as calcium-based extenders were also detected. FTIR analysis provided important information regarding the binder composition, mainly modified alkyd resins being identified. Additional information related to the existing chromophores as well as specific binder-pigments interactions could also be highlighted within the HSI data sets.Overall results provide new insights on the complex chemistry of this new range of materials, which could help future investigations carried on street art graffiti, contemporary murals, or mixed-media artworks.