Restoration of Paintings and Art Conservation In Our Lab: Protecting Public Art With Anti-Graffiti Coatings Varnishing Murals

Although the mural may seem out of reach, taggers find ways marking community art by shooting the paint with blasters. The graffiti on this mural goes up about 20 feet.

Forethought about protecting murals from graffiti is an essential part of the planning for art in a public place.

First of all, you need to understand the “why” before you can discuss the types of protective varnish to use form anti-graffiti protection.

These insights are offered to you by the professionals hired by the City of Los Angeles to consult on protecting and preserving art, paintings and murals, Fine Art Conservation Laboratories.

Murals are part of a community’s heritage, part of the architecture, part of a community’s vibe and culture. They are not just a decoration. In the professional mural conservation field, when asked how long should art last, we think in terms of “generations.”

Professionals mural conservators (restorers) are bound by Ethics and Standards of Practice. These standards would theoretically imply:

1. We do no harm to the original artwork... the materials we use should not cause harm to the original mural as they age or if they have to be removed

2. This means, also, that anything we do to the mural should be reversible or safely removable in the future... even distant future.

Here’s the problem to be solved: Murals painted in acrylic paint remain very soluble-dissolvable (Keim and oil to a lesser degree but still...) forever. So, cleaning with anything except water is a problem. Of course, none of the stuff sprayed, spilled or deposited on murals is cleanable-removable in water. Solvents and citrus based strippers used to remove graffiti also attack-remove the original paint.

In other words, ANYTHING that is used to varnish the mural, will become part of the mural because it cannot be removed safely (for the artwork). So, let that idea percolate for a moment... if the varnish yellows, that will be the look of the mural in the future and there will be no way possible to remove the yellow. If the varnish cracks and peels (obviously unevenly) then you can’t remove it to redo it later.

This photo shows a hazy brown varnish layer over the artwork.

Despite this warning or inevitable negative situation, some entities have chosen a chemically unstable hard resin “permanent” protective varnish over a chemically stable sacrificial layering of removable or “thinnable” varnish. I think their choice is based on ignorance based on the opinions of non-conservation-preservation services within their bureaucratic channels, not because there has been a logical choice specifically for the benefit of artwork/murals.

The two schools of thought

for the choice of protective layer or varnish are:

1. The City of Los Angeles has adopted a policy, with the excuse of future minimal maintenance, to use a “permanent” hard coating. The name is “GCP 1000”

Polyurethane Topcoat. Here is the link for application instructions. I suppose that because this is a commercial product, that this appeals to bureaucrats. I’ve also been told that some graffiti can be removed from this protective layer with a commercial cleaner called Goo Gone (another long term preservation problem).

The Office of Cultural Affairs chose this material at the recommendation of their graffiti abatement contractor. The photo below shows a brown varnish under the graffiti. This was a permanent hard coating applied over a sacrificial varnish, that was not yellowed or brown.

2. A “sacrificial” varnish layer is one that is applied so thickly that when tagged, the graffiti can be removed along with a layer of varnish without having to remove all the varnish. This means that the cleaning-removal solutions don’t come into contact with the original paint. After the graffiti removal, the surface needs to be re-protected or in other words, the sacrificial varnish layers need to be reapplied.

The resin used for the sacrificial layers is not a commercially available product, but can be purchased from conservation suppliers. The resin used is Rohm and Haas’ Paraloid B72. We usually spray apply 4 heavy coats of 15% solids (in xylene solvent). Then we follow up with 4-5 coats of 30% applied with rollers as thickly as can be possible applied without creating drips. On the mural in the video below, the artist originally thought to apply the thicker sacrificial layer only up on the wall about 8’. But yielded to reason when I showed him the nefarious techniques some vandals use to spray way up high on walls. So, we applied all the layers over the entire mural.

This photo shows the before and after of removing a decade of graffiti off of a thick protective sacrificial varnish.

Here is a quick video of applying the sacrificial varnish layer to a new mural at street level in Northridge (Los Angeles), CA and a short testimonial for our collaboration.

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