# Unveiling the Secret Chemistry of Street Art by a Multitechnique Approach

## TL;DR

This study analyzes the chemical composition of spray varnishes used in street art to help develop conservation guidelines.

## Contribution

The paper introduces a multitechnique approach to identify specific binders and additives in modern street art varnishes.

## Key findings

- Acrylic, polyvinyl acetate, and styrene–acrylic resins are primary binders in spray varnishes.
- Additives like polyethylene and polypropylene glycol are commonly used in street art varnishes.
- Organic dyes and pigments such as PY74, PO36, rhodamine, and phthalocyanine are identified in the samples.

## Abstract

In recent years, graffiti and street art have gained recognition as legitimate art forms, deserving of the same care and attention as traditional art. As a result, conservators and restorers are now working to develop standardized guidelines for the cleaning, conservation, and restoration of these vibrant works. Our study takes a closer look at the materials used in street art, specifically the spray varnishes used by artists. Samples from two murals created in 2021 in Bari, Italy, are analyzed using a range of advanced techniques such as attenuated total reflection Fourier‐transform infrared spectroscopy, reversed‐phase liquid chromatography coupled with UV‐Vis and electrospray ionization mass spectrometry (MS), and laser desorption ionization MS as well as pyrolysis–gas chromatography/MS. Acrylic, polyvinyl acetate, and styrene–acrylic resins are identified as the primary binders used in street art spray varnishes, along with common additives such as polyethylene and polypropylene glycol. The organic dyes and pigments, such as yellow (PY74), orange (PO36), red (rhodamine), and blue (phthalocyanine) hues used to create colorful images of street art, are also characterized. This study demonstrates the importance of a multitechnique approach in understanding the complex chemistry of modern spray varnishes used in street art.

Two murals created in 2021 in Bari, Italy, have been analyzed by attenuated total reflection Fourier‐transform infrared spectroscopy, reversed‐phase liquid chromatography coupled with UV‐Vis and electrospray ionization mass spectrometry (MS), laser desorption ionization MS, pyrolysis–gas chromatography/MS. Acrylic, polyvinyl acetate, styrene–acrylic resins as primary binders along with additives such as polyethylene and polypropylene glycol were identified in spray varnishes.© 2025 WILEY‐VCH GmbH