Wednesday, February 15, 2017

Painting on Plexiglass- Maybe Not!

I think it is a tendency for artists to want that certain something, that technique, material or magic potion that will distinguishes their art from others. God knows I have tried a lot of crap. Lately painting on acrylic panels seems to be one of them. I noticed in a recent issue of an American artist's magazine "The Artist's Magazine" an artist mentioning painting on acrylic panels. It set off a warning light in my head as I have had talks with my husband over the years about this practice. He is a physicist ( Brown/ University of Rhode Island) specializing in the development of new materials and has run product tests for me over the years. He has debunked and confirmed manufacturers claims about their painting materials. (Micheal Harding's stuff is the real deal) One thing he has cautioned me me against is plastic as a painting support. Many artists painting on Plexiglas" and recommending it cite no scientific studies as to its durability.

I excerpted the paragraph on 'acrylic' substrates from a paper from the The Department of Art Conservation at the University of Delaware on painting supports. It covers all supports and though not Jane Austen is an informative read. It  does give some good advice as to its safest use.

"Polymethyl Methacrylate (e.g. Plexiglas) Plexiglass is one of several trademarked names used to market clear sheets of polymethyl methacrylate, a material that is a popular support among artists. These sheets tend not to contain potentially problematic additives such as those found in polyvinyl chloride- and polycarbonate-based materials. However, Plexiglass will expand and contract in response to changes in temperature and humidity, leading to eventual warping or bending of the support. This can be problematic if very brittle materials are used in the paint and/or ground layers (e.g. oils, alkyds, certain resins) as delamination and cracking may occur as the support expands and contracts. Watercolors, tempera, and most gouache paints should be avoided. The glassy-like surface of Plexiglass makes for a surface that can be easily scratched and can build up a static charge that can attract dust particles. Plexiglass is prone to yellowing if exposed to UV light and can be extremely sensitive to certain solvents; artists should avoid bringing acetone, aromatics, and other solvents to surface of Plexiglas, sticking instead to water or mineral spirits-based products. Finally, and perhaps most importantly, Plexiglass supports are inherently brittle and easily shatter or crack if dropped or damaged. If an artist insists on using a polymethyl methacrylate support, the best procedure is to initially sand the surface in order to provide some mechanical tooth to improve the adhesion of the paint and ground layers. Artists should consider painting and priming with acrylics if using Plexiglass as they do retain some degree of flexibility. Avoid installing inflexible hardware directly into the Plexiglass, choose thicker rather than thinner sheets, and use a channeled frame to house/display the Plexiglass."

I have found that the  National Gallery of Art Department of Conservation a wealth of accurate information. You can call them and email them- a fine example and one of the few examples of taxpayer money going to help artists.  When I have a question they are my go to source.
Much of what is online about artist materials is for amateurs and often wildly incorrect. It is best to find a source like our National Gallery and the University of Delaware's School of Conservation for the most unbiased information. There are others like the Metropolitan Museum, Fogg etc.  I have contacted them as well as others.The jobber of said Plexiglas said it would last forever. 

This is an updated version of the book I already have. A lot of new research and information has gone into it.

"Unfortunately, “plastic objects are among the most vulnerable found in museums and galleries.” "

Here is a discussion on WetCanvas- an online painting forum on acrylic supports.
From WetCanvas 08-17-2004, 09:29 AM
As a sign manufacturer, I have great deal of experience with 'plastics' - acrylic, lexan, styrene, pvc etc. I would be very skeptical about using acrylic as an archival board. You not only run the risk of your paint delaminating, but also face the fragile nature of acrylic which leaves it susceptible to cracking. Also, depending on whether it is cast or extruded acrylic, the chances are that you bought extruded, the plastic will warp with larger sizes. Acrylic gesso may not be the proper ground for the initial priming because it doesn't have a proper chemical bond...the acrylic gesso (as a ground) should be applied after the plastic has been primed. The only primer I know that can be used properly for acrylic priming is a lacquer based primer similar to automotive paint primers...anything else is a temporary paint job. Almost any substrate can be turned into a suitable ground with proper preparation and priming, but I personally wouldn't use acrylic for archival fine art. No problem for experimenting, studies and personal projects.

Do your own sleuthing, don't take my word  on this, make sure the materials and practices you employ have scientific backing.

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