Recently, we had a question about SID effecting the paint on the panel edges. An artist was concerned about paint on the edges of the untreated panel, not cradle, and how that might effect his work long term. Below, Dana Brown answers the question.
“The condition of SID is one of acrylic paint and acrylic dispersion ground (acrylic gesso). We make broad recommendations to sealing the painting surfaces of wood, as a separate step from priming, primarily due to the common use of acrylic gesso as a primer, but also to maintain a painting surface that is as acid-free as possible. It is also based on an understanding that proper habits can become good practice when using various materials. We know that sometimes artists will pick up a piece of wood to use as a substrate, not knowing its density or acid-level, and sealing the panel will give the painting a ‘fighting chance,’ of lasting.
Because of the differing characteristics of each paint type mentioned, I will address each separately.
Acrylics dripped over the edge (that thin, 1/8” thickness) will encounter some level of acids. It will also take on a level of discoloration. Support Induced Discoloration (SID) is not a dark blackening or even a dark browning of the paint film, and it is generally only noticeable in areas of white and generally only in the wettest of applications. This is why it is commonly associated with the applications of acrylic gesso, applied directly onto a wooden support. Areas of color mixtures or darker colors, especially when applied undiluted or more thickly, will not display noticeable discoloration in the same sense. If the entire acrylic painting is done onto an unsealed wooden surface, the levels of acids in the wood (which vary greatly from wood species and type) can cause damage to the artwork. The amount of acid or discoloration from a 1/8” edge is very small and will not put the painting in jeopardy of lasting or any continuous damage. The acid level in our hardboards is nearly neutral at that, and it is one of the reasons that we selected aspen as the overlay for our product. To sum up in reference to acrylic paint, if the drips or painted edge are white, applied quite wet, or thinly, discoloration may be noticeable. To prevent this, you can apply GAC 100 or PVA Size to the edges to create a barrier seal to the exposed, cut edges. For most painters’ practices, the effect of a few drips over the edge of a 1/8” thick panel is not damaging to the artwork or its appearance, and its durability is not at risk.
Gouache and oil colors are not susceptible to SID and the reason to carefully seal the panel before priming is again a rule of thumb, put forth by the general practice of acrylic dispersion grounds and acrylic based priming layers. The main issue with gouache dripping over the edge or being painted on the edge of a dark, brown panel is mainly that the edge may not be sufficiently absorbent to give a lasting mechanical bond between the paint and the panel’s edge. Also, the dark, brown tone may cause paint applications to look darker, requiring multiple applications.
For oil colors, there is also no risk of SID. The risk is more of great amounts of oil paint, directly applied to wood, soaking into the wood and oxidizing within the structure of the wood. This is even contentious amongst art conservationists and may be less of a risk than previously believed. The 1/8” thick edge of a panel will not allow for a risky level of oxidation within the wood support. The oils in oil colors will actually pass on some conditioning or preservation qualities to the wooden support, similar to applying oil to wooden furniture to recondition it.” -Dana Brown Artist & Customer Support at Ampersand
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Gessobord™ is the most trusted pre-gessoed wood panel by artists for their work. Why?
The superior quality acrylic gesso ground does not dull colors and the wonderful lightly sanded surface provides exceptional brush control. 88% thicker gesso than other brands.
Made with Ampersand’s 1/8″ True Artist Hardboard™ and Archiva-Seal™ technology, the surface is acid-free, non-yellowing, and archival. Perfect for all painting styles with oil paints, acrylics and mixed media.
Only Ampersand builds their cradles by hand with premium grade 13-ply birch plywood for maximum stability and a clean, finished look from edge to edge.
All of our Gessobord panels and the Museum series panels are made in the USA.
Only Ampersand™ uses true high-density hardboard made from US-grown and renewable Aspen wood fibers. Gessobord is archival, eco-friendly and formaldehyde-free.
In our “Painting on Panels” series, I’ve been sharing a lot of tips on working on wood panels. To keep it all in one place, this is a list of resources for understanding wood panels and the best practices in working on them for producing long lasting art. Working with Masonite — Read about what makes Ampersand’s hardboard different than Masonite, archival to use and the differences between other panels in the market. Solid Wood vs. Manufactured Wood Panels — The top 4 things an artist should consider when choosing a panel type. Differences between HDF & MDF — What to look for in choosing a panel, whether it is hardboard, HDF or MDF. Understanding the properties of each and how they will effect your artwork long term. Cradling and Supports — Why it’s a good idea to brace large manufactured panels. Sizing — Why it is important to size panels before priming and how to choose the proper products for good adhesion. Oil Priming — All raw wood panels need to be sized and primed before painting. This outlines the basics on priming with an oil ground and which products to use for the best results. Acrylic Priming — Step by step instructions for using an acrylic dispersion groung to prepare wood panels. ™ Support Induced Discoloration — The reasons that SID occurs and what you can do to prevent it. Take note that Hardbord and Unprimed Basswood are on sale now up to 50% off list price through the end of February. Here is a list of the participating dealers: www.ampersandart.com/retailers2/promo-retail All things Ampersand, Karyn Meyer-Berthel Artist & Social Media Specialist Ampersand Art Supply Click here to explore the full selection of Ampersand panels and tools.
In order to give a panel extra support, many artists produce a bracing system (cradling) for their panels. While this is not an option for solid wood panels due to their expansion and contraction over time, manufactured panels are structurally sound enough to be cradled. For panels over 24″ cradling is advised.
Elaine and Veronica inspecting panels
Cradles are generally a separate unit the size of the panel that is attached to the back using carpenters glue and C-clamps. Larger size cradles will generally have cross-braces, much like stretcher bars for canvas. When choosing a wood for your cradle, it’s best to go with high quality multi-ply plywood, as this will give you the best protection against warping. Solid woods are to be avoided, as they have a uniform grain that will warp over time in a thin strip. Do not nail or screw the cradle onto the panel, or you will have a blemished surface that is certain to deteriorate over time.
Save yourself the trouble of all this carpentry work by using an Ampersand cradled panel. Only Ampersand builds their cradles by hand with premium grade 13-ply birch plywood for maximum stability and a clean, finished look from edge to edge. Choose from 3/4″, 1.5″ and 2″ Deep, all carefully made by hand in Buda, Texas.
Ampersand Claybord™ and Gessobord™ panels are now available in a new 1.5″ Cradle Profile that offers you more flexibility for hanging and framing your work. Featuring a 1.5″ total depth, this new cradle profile is handcrafted with premium grade 13-ply birch plywood, designed to fit both standard canvas and floater frames. The cradle can easily be painted or stained to complement the artwork or primed with gesso to wrap the image around the edges.