Sea Salt And Unstable Paints Explain Why Murals Chip And Fade Away
Communities or businesses sometimes commission artists to create murals to spruce up boring walls. But when left to the elements, these artworks often fade or chip over time. A new study looked into the process of how murals degrade over time, and what they’ve found can help preserve public street art.
A colorful freshly painted mural can drastically brighten the appearance of a street and make it a more welcoming place. That’s why shop owners might have their walls or shutters decorated, or why local community organizations commission artists to paint murals in public spaces. After a few years, though, the murals are no longer fresh and bright. The paint has chipped, the colors have faded, and the streetscape is starting to look a bit tired again.
The usual way to fix urban art is to get the artists back in and have them fix the mural. But what if there’s no budget for that? Researchers at the University of Vigo in Spain thought that it could be useful to know exactly what happens to murals over time, so that people can take steps to protect the new art on their walls as much as possible.
There wasn’t a lot known about the science of degrading murals yet. In their article in The European Physical Journal Plus the scientists speculated that this is perhaps because urban art is badly defined (and sometimes clandestine) as well as generally fleeting: Not all street art is intended to last, which makes it hard to study how to preserve it.
To learn more about the ways that murals are affected over time, they followed 25 murals over the course of two years. All murals were in Galicia, an area in the North West of Spain along the Atlantic Coast. In 2018, when the murals were new, the researchers collected some paint samples and took photos of the art. In 2020 they checked them all again, and quite a lot had changed.
Even in such a short time, several of the murals were lacking quite a lot of color, but the fading rarely affected all colors in the mural. In a chemical analysis of the paint samples, the researchers found that certain components in the paints itself, as well as the base that was used were more likely to fade than others.
Other types of damage that were common among the murals they tracked were cracks in the paint layer, flakes of paint that came off, or entire pieces of the top layer of the wall that had chipped off – paint and all.
From studying the locations of the murals and comparing the damage to each of them, the team noticed that murals closer to the sea had more damage resulting from salt deposits, and murals in humid locations (for example out of direct sun) were more likely to be damaged by moss growth or other biological causes.
Overall, the information they collected could be useful for anyone hoping to commission a new mural. But keep in mind that this was only one study done in a specific area of Spain, and that conditions can be very different in other parts of the world. Still, it’s probably a good idea to try to keep sea salt far away from street art if you want to keep it looking fresh.
