Solar radiation is one of the deterioration factors par excellence of modern urban artworks, as among other manifestations, it causes loss of colour. This deterioration can compromise the durability of the works, although it is not known to what extent this durability can vary depending on the substrate supporting the paint. We evaluated the susceptibility to sunlight of 10 paints of differing compositions as typically used by urban artists, by exposing them, applied to concrete and brick, to artificial sunlight ageing test in laboratory conditions. Colour changes over time were studied, along with mineralogical (x-ray diffraction), chemical (scanning electron microscopy-energy dispersive x-ray spectroscopy) and physical (contact angle and peeling tests) changes. The durability of the paints on these substrates depends mainly on the paint composition (base, pigment and filler) but also on the type of substrate, as this influences paint adhesion capacity. The greatest colour modification was detected in fluorescent paints, which lose colour due to degradation of the organic phase, and with aggravation of defects during drying, eventually detach from the substrate.

太阳辐射是现代城市艺术品卓越的退化因素之一，除其他表现外，它还导致色彩损失。这种变劣会损害工件的耐久性，尽管尚不清楚该耐久性能在多大程度上取决于支撑涂料的基材。我们评估了城市艺术家通常使用的10种不同成分的涂料对日光的敏感性，方法是将它们暴露于混凝土和砖中，并在实验室条件下进行人工日光老化测试。研究了随时间变化的颜色，以及矿物学（X射线衍射），化学（扫描电子显微镜-能量色散X射线光谱）和物理（接触角和剥离试验）的变化。这些基材上的涂料的耐久性主要取决于涂料的组成（基础，颜料和填料），还取决于基材的类型，因为这会影响涂料的附着力。在荧光涂料中检测到最大的颜色修饰，该荧光涂料由于有机相的降解而失去颜色，并且在干燥过程中缺陷加剧，最终从基材上脱落。