Amanda Norbutus is in the Preservation Studies doctoral program at the University of Delaware, and has her undergraduate and master’s degrees in chemistry. Her presentation first outlined the state of public murals preservation and the issues faced today, then described current research into protective coatings for public murals and discussed a case study of a mural by Meg Saligman in Philadelphia that has been successfully treated.
The “Contemporary Mural Movement” refers to public murals produced since the 1960s (see cool book) and Amanda noted that there are more than 350 public art programs across the US that have facilitated the production of these murals. The murals often address themes of heritage and social and political equality. Loss and damage are rampant for a number of reasons: the murals are often spontaneous, not planned with long term preservation in mind; they are subject to extreme outdoor conditions; and they suffer from a lack of funding – while money is pledged for their production, none is usually allocated for preservation. The murals often also fall under various jurisdictional disputes – no one is quite sure who is responsible, or who has the right to make decisions about the wall or the image. To address some of these issues, Heritage Preservation has a program called Rescue Public Murals which carries out identification, documentation and conservation of murals, provides a network for those working on their preservation and researching best practice for mural production and conservation, and conducts fundraising (you can sign up here to get on RPM’s mailing list). They also have a partnership with ARTstor Digital Library to preserve images of murals, as not all can be physically preserved; there is a Community Murals collection in ARTStor. Amanda noted one prominent case in which Ken Twitchell, an artist who had painted a mural (Homage to Ed Ruscha) on a federal government-owned downtown LA building, received a $1.1 million settlement after the mural had been painted over.
A few of the biggest problems facing murals are graffiti, physical destruction, and desaturation as the paint layers weather and are exposed to UV. UV radiation causes cracking, color change and fading. Oxidation chain reactions are the culprit on a chemical level. Research has been ongoing to look into protective UV barrier coatings. Some limitations are – scale, access, acceptability by stakeholders, safety (VOC’s), and ease of application. Some of the categories examined include acrylics, waxes, polyurethanes, and silanes.
In a study that began in 2005 at Delaware, Jessica Keister painted out more than 700 samples of blue, yellow and red colors of various types of paints from Golden, Novacolor, and Keim, in addition to some fluorescent colors. As coatings, she looked at B72 with Tinuvin, Novacolor, Golden MSA varnish, and a Triangle Triton coating (not reversible). The samples were placed on the roof and exposed to weather for three years. In 2008, Amanda began looking at the samples, noting the differences between colors – Hansa yellows did best – and paint systems – Golden heavy bodied acrylics did best. Golden MSA varnish seemed to protect the samples best – the Triangle coating was better at keeping mold and dirt off the surface, but its irreversiblity deducted crucial points from its usefulness. There was some success with B72 and Tinuvin (UV stabilizer), and in general two coats worked best of the protective layers. Amanda noted that products commercially sold as UV protective are not always so – she cited a test done by muralist Ed Massey on an industrial polymer coating that was purported to have a UV stabilizer, which failed completely. Finally, there needs to be more research into reversibility on a practical level, whether coatings can be effectively removed without affecting damaged paint beneath. Here’s more detail from Amanda about the parameters of the samples on an RPM blog post from 2008.
The Meg Saligman mural in Philadelphia is called Common Threads (1998), and when RPM assessed it in 2009 it was extremely faded. The artist didn’t want to repaint it, as she felt she would change it too much. Together with RPM and Winterthur Art Conservation faculty and students, the artist agreed to apply a coating of Golden MSA – but they had to get an exception from the EPA to use it on such a large scale. Applied after surface cleaning, this coating resaturated the colors significantly. They also then did some retinting with Sher-Cryl (Sherwin williams acrylic) and pigments (envirotint?) over the coating, then applied another layer of the Golden coating.
A key point is to work with muralists to prevent some of these problems from the get-go. Amanda noted that when doing this it’s important to address the bottom line – money – and emphasize that in the long run it is cheaper to use better products first rather than having to repaint or conserve a mural later.
She ended with a summary of other key points to remember when working with murals/muralists:
- Get involved with the community
- North facing walls are best
- Clean and prime the wall first (amazing but often not done!)
- Choose the right palette – no fluorescents, they fade fast!
- Use quality paints
- Use a coating layers
- Use a UV absorber
- Create a maintenance and monitoring plan
- Consult with conservators and scientists when in doubt