More about Painting Supports

Rigid panels have been used as painting supports for millennia, and are an excellent alternative to canvas. There are oil paintings done on panel that are still in excellent condition after 500 years. The greatest flaw of canvas is that it is not rigid, and the condition of many older paintings have suffered because of this fact.

Panels can be made to have a wonderfully smooth surface that is excellent for painting in detail. For those that desire a more textured surface, canvas can be glued to the panel, for the benefits of both.

A lot of materials are suitable for use as painting supports. I have organized some of the more popular choices into groups.


WOOD


Wood is one of the oldest painting supports, having proven itself in use over thousands of years. Many different species are suitable. Historically, Poplar was a common choice in Southern Europe, Oak in the north.

Wood has some drawbacks. It can rot, and be attacked by pests. Wood is not always dimensionally stable, and can warp. The susceptibility to all of these problems will vary by species.

With the right preparation, these issues can be minimized. Wood should be aged properly to ensure that it is dry and acclimated to its environment. This process used to take up to ten years. Nowadays, most woods are kiln dried, which does not always ensure a wood is completely dry. I try to work around this issue by using old or reclaimed wood.

Panels made from wood were usually braced in some manner to make them stronger and to resist warping. There were a variety of ways of doing so. Ongoing research by conservators suggests that these methods may do more harm than good. Braces can't stop a panel from eventually warping, and in the process put extra stress on the wood.

I have chosen not to brace my panels. The method I have adopted instead is to size and gesso the panel equally on both sides to ensure it is sealed. This is based on historical recommendations and backed by modern research. I use wood that is as close to quarter sawn as possible. This is wood that is cut down the center, so that the grain runs parallel along its length, making it more likely to be warp resistant.

Plywood is made by gluing many thin sheets of wood together, in alternating layers. This makes a solid sheet that should be stronger and more warp-resistant than the same wood in regular form.

Plywood suffers from drawbacks unique to its construction. Boards can warp, plies can de-laminate, and the glues used to hold plies together can leach out and cause damage to the paint. The quality and price of modern plywoods is all over the map. I've had a lot of issues trying to use plywood as a painting surface with traditional gesso. Soon after making them, my panels developed micro-fine cracks, caused by the wood grain swelling from moisture. This is fairly common, from what I understand. I would suggest doing your own tests and experimenting, before using plywood on anything you consider important.


ENGINEERED WOOD PRODUCTS


Products that have been manufactured using ingredients derived from wood. Their benefit is that they are more dimensionally stable than wood, should resist warping, are widely available, and inexpensive.

Hardboard, aka Masonite, is a type of dense fiberboard. It is made from wood fibers that have been compressed under extreme pressure, until they are bound together. No glue is used in this process. Hardboard is strong, dense, and has no grain.

Hardboard panels have been in use long enough to get an idea of their longevity, with mixed results. Some vintage paintings are in good shape, while others have not fared well. "Tempered" hardboard, has been coated with oil to make it more weather resistant. There are cases where this has reportedly leached into the paint surface and ruined it, so tempered products should probably be avoided.

The majority of premade "archival" artists panels are made from some kind of hardboard. Without knowing specifics about how a panel is made, I would think twice about using them for anything but smaller, more informal works.

MDF or Medium Density Fiberboard is made from ground wood fibers bound together by a glue or resin. It is weaker and less dense than hardboard. The resin used to bind the wood fibers poses a health risk as it is usually formaldehyde-based. Protection should be worn when working with MDF.

MDF is a relatively new material, so long-term permanence is still open to debate. How long the resins that hold the material together will last is a big concern. MDF is relatively soft, so it can be dented easily, especially around the edges. It can also swell if exposed to water. I would recommend sealing MDF on all sides before use.


METAL


Metal has been used as a panel support on a limited basis for centuries. Rembrandt used copper for some of his smaller works, and these are still in excellent condition. Provided that there is a sufficient bond between the paint and metal, it is in many ways the ideal surface. Metal is rigid, stable, and expands and contracts relatively little. The drawbacks include the added weight and expense of many metals such as copper, and the possibility for corrosion unless sealed from the atmosphere.

Malachite

I don't normally use a green in my palette. In the past, I've made my greens by mixing yellow and blue together. So I thought it would be fun to make a new color, and try out some new preparation techniques at the same time.

The Old Masters would have had limited sources of green pigments. Bright greens would have been derived from copper. Malachite is a mineral form of basic copper carbonate. A cheaper synthetic copper green, known as verdigris, was widely used as well. This was made by tarnishing copper. A sheet of copper was placed inside a jar full of vinegar. The green that formed on the surface could be scraped off and ground into a pigment. Verdigris is considered inferior to the natural mineral, so I chose not to use it.

Malachite has a blueish-green color, very similar to the patina one finds on copper metal left outdoors.

Malachite is lightfast, but sensitive to the acids found in oil paint. This fact has lead many experts to not recommend its use. However, it's well preserved in many Old Master paintings, so there is reason to believe that some of these concerns may be misplaced. There is evidence that in more well-preserved pictures, copper pigments were coated with some kind of protein. This protein formed a protective barrier around the pigment particles that stabilized them. I came across a treatment along similar lines developed by the artist Michael Price, and decided to try it.

The basic technique is a process known as levigation. It takes advantage of the fact that larger particles are heavier and settle more quickly in water than smaller ones. You add water to the pigment, stir the mixture , and then pour off the contents. The larger particles settle quickly and are left behind, the finer go with the water. With this method, one can separate a pigment into a whole range of different particle sizes. In practice, its difficult to get a very precise separation.

By adding protein, we are able to make this method more effective. The source of our protein will be a solution of eggyolk and water.

The malachite is first crushed into a coarse powder in a mortar and pestle. This powder is washed in water several times, then allowed to dry. Malachite is moderately toxic, so I always wear gloves, a respirator, and work outside on calm days.















Crushed malachite being washed in water.















I prepared the water/egg mix.















I slowly added the mix into the malachite and stirred them together.















You can see desired effect as I tilt the bowl. The larger particles have settled to the bottom.

The liquid is then poured off into another bowl, leaving the sediment at the bottom.















The process is continued over and over again, creating more and more bowls full of finer and finer particles. They are left to dry.

After they had dried, I went back and reground the coarsest pigment again.















The malachite is ground on a marble slab with a muller. This was followed by more protein treatment. I ended up repeating the whole process over again three times.















I'm very satisfied with the final color. I feel it was worth all of the work in the end.