Sedona, Arizona is well known for its beautiful red rock cliffs and spires but it’s being loved to death by its 2.5 million annual visitors. Too often, hikers and sight-seers mark our red rocks with scratches, charcoal, and even paint, leaving an ugly mess for visitors to see and Friends of the Forest to clean up. The Friends of the Forest graffiti team is a volunteer group that works closely with the US Forest Service to remove graffiti on Red Rock District of the Coconino National Forest and to educate hikers to “see something, say something.” As noted in Jerry Piepiora’s article last month, anyone seeing vandalism should report it directly to the Forest Service or to the Friends of the Forest at firstname.lastname@example.org.
The first time I joined the Friends of the Forest graffiti team on an outing, I was impressed with how effective scouring the sandstone with sand paper and water was in removing graffiti. But when we removed graffiti from the dark, patinated rocks using that same aggressive scrubbing, we were leaving unsightly scars. As an old faux finisher and fresco artist, I thought we could use another tool in our toolbox, so I put together a painting kit very similar to ones used by native artists a millennium ago here in red rock country.
Patina, or desert varnish, is the thin dark red to black coating found on exposed rock surfaces in arid regions. Desert varnish forms as a result of water, microbes and minerals interacting over a long period of time. Desert varnish forms slowly—only 1 to 40 micrometers per 1000 years (a human hair is about 1 micrometer in width). When a vandal gouges his or her name through the fragile desert varnish, it will not recover in our lifetimes.
To repair damage to patinated rock, we take a “less is more” approach. First, we gently clean the damaged area with a damp rag to remove dust and debris. Then, to replicate the look of darkly patinated sandstone, we use a mixture that we make from very finely milled pure iron oxides. These mineral oxides occur naturally in patinated rock and are lightfast and permanent.
Our black, brown, and red oxides were donated to us by Larry Fricke, President of Fricke Dental Manufacturing International in Streamwood, Illinois, after visiting Sedona and learning about our graffiti efforts. A beautiful orange oxide was donated by Friends of the Forest member, Pam Milavec. This material is a pigment-grade iron oxide that was collected and produced by Iron Oxide Recovery, Inc. from an acid mine drainage treatment site in Pennsylvania. White and yellow pigments that we use to replicate the look of lichen come from my studio.
We wet the dry pigments with water, then combine the oxides with egg yolk as a binder. The egg yolk/mineral pigment mixture, or egg tempera, is then dabbed onto the damaged rock with a natural sponge to create the look of patina and disguise the damage. The resulting paint dries to a matte finish and is resistant to rain and sun damage.
We have used this additive technique extensively on Bell Rock, Slide Rock and West Fork in the areas that are heavily patinated (and heavily vandalized). We revisit the sites frequently to see how our work is holding up, and so far, the repairs have lasted three years and counting without fading or flaking off. On each work trip we remind hikers and visitors to “see something, say something!”
If you would like to join us and help keep our environment a unique place to visit and explore, please visit our website https://www.friendsoftheforestsedona.org.
This article was contributed by Nori Thorne.