All paints, pastels and watercolor paper I use are of professional quality. The watercolor paper is cotton, acid free and 140 lb. Manufactured from pure cotton fiber, these papers are so durable that it is said they will remain beautiful and vibrant for centuries without conservation, if stored and handled properly.
The following article is from Russell’s West Quarterly, Volume 2 issue 1, pp. 9-10, a publication of the C. M. Russell Museum. Visit their web site at www.cmrussell.org.
ARCHIVAL OR MUSEUM QUALITY MATTING AND FRAMING
The first step to assuring the longevity of a watercolor is its preparation. If possible, when the work is acquired, find out if the artist used acid-free paper. If not, even the most careful handling will do little to overcome the inherent problems that exist with acidic paper. Acidic paper is cheaper, made from wood pulp. The best papers are made from 100% rag fiber (cotton, linen, etc.) and can last forever if properly handled. Think of the difference between a very old book, printed before the wide-spread use of wood-pulp paper, and a 20th century paperback book whose pages are crumbling after only 10 or 20 years.
If you acquire the work unframed, request that your framer use archival or museum quality matting and framing. This means using 100% rag fiber matting in either 4- or 8-ply thickness. Acidic mat stock can, at best over time, burn the watercolor where it touches it, and at worst, host parasites that are destructive. The front and back mats should be hinged at the top with white linen tape or Japanese rice paper, and rice or wheat starch paste. Never allow the use of transparent or masking tape, which can stain and burn the mat over time.
Sometimes watercolors are framed without a mat, in which case the framer should use spacer strips of 100% rag fiber matting between the work and the glazing. The spacer strips will be covered by the framing and prevent the watercolor from sticking to the glazing.
Glazing is another critical aspect of the framing. Resist the urge to use non-glare glass, which is finely etched to reduce reflected light, and actually absorbs light. Instead, opt for glazing with materials such as UV3-coated Plexiglas or Denglas. Be sure not to use glass cleaners that contain ammonia on Plexiglas or any acrylic glazing (it will yellow). Instead, use a very mild detergent solution and a soft cotton cloth, or a special cleaner made for Plexiglas.
The actual framing materials — wood, metal — are not as critical as the thickness of the stock and the depth of the rabbet — the lip or groove that holds the watercolor and glazing in frame. The weight of a watercolor is affected by its glazing. Larger works require larger glazing, and need a deeper rabbet. If the frame stock is too thin or slender, it can bow under the weight of the contents, which might pop out.
Light is the double-edged sword of art ownership. Of course you need light to appreciate the work; however, light is one of the biggest enemies of fragile watercolor pigments. So, NEVER hang a watercolor where it will receive any direct sunlight. Over even a small amount of time the ultraviolet light in sunlight can begin to fade the pigments and dry out the paper. Longer-term exposure may further embrittle the paper, either bleaching-out or turning an acidic paper an ugly yellowish hue (an acid burn).
It is advisable to hang a watercolor in a room with diffused incandescent or halogen light. Fluorescent lighting is as damaging as sunlight, producing ultraviolet light in high concentrations. If lighting is applied directly to the painting, be sure the light fixture is at least 8 -10 feet away (a ceiling spotlight with a low emission is best). To further shield the watercolor from damaging light exposure, use protective glazing such as UV3-coated Plexiglas in the framing.
Have you ever wondered why museums are often colder in the winter and summer than other public buildings? It is for one reason: conservation of the artworks and cultural objects. The best environment for art is filtered air below 70 degrees at a relative humidity between 50-65 %. Usually filtration on your home HVAC system is adequate, unless you live in an area of high pollution and dust. Temperature and humidity fluctuations play havoc with organic materials such as paper, so even if it is not possible to keep art at the optimal conditions, it is more important that it is not subjected to dramatic changes. Thus, avoid placing a watercolor over a heating vent, or over the fireplace, or by the front door. Even an outside wall could be problematic if not properly insulated.
If one has an understanding of the care required, a watercolor can be safeguarded to retain most of its original condition. There are watercolors that are over 100 years old that are wonderfully fresh and crisp because they have been protected. Frequently, however, older watercolors are light-struck, a term that refers to the fading of some pigments, and the virtual disappearance of others. Nothing can restore the pigments to the original state. Don’t let this happen to contemporary pieces that you acquire, or to older pieces that come into your possession. With care, watercolors can last for posterity, and ensuing generations will appreciate the dedication to longevity.