storing, mounting & framing

Paper is an organic product, and requires special handling to prevent damage both before and after a painting is made. In addition, watercolors are not slathered on the paper in a coating of binder, but lie naked on the surface of the paper over a very thin binder of gum arabic. This makes watercolors vulnerable to damage.

This page describes the main environmental hazards to both unused papers and finished paintings, and describes methods of storage, matting and framing that will help preserve your art.

paper hazards

It's most economical to buy paper in bulk lots, which means you'll need to store paper until you can paint through the last shipment.

Whether you're considering the long term storage of unused paper, or proper display of finished paintings, light and moisture are the worst environmental hazards you should try to control.

If you can store papers or paintings so that they are flat, dry, cool, and out of direct sunlight, you should be fine.

Paper exposed to direct sunlight is at high risk to yellowing and embrittlement. The fact that sunlight can reach it at all means that humidity and temperature changes will affect it as well.

Humidity at either extreme is a hazard. If the air is too dry, the paper and its surface sizing will become brittle; if the air is too moist, mold or fungi are more likely to grow. High humidity also promotes chemical decomposition of the paper by acids transported from the air. The optimal relative humidity for papers or paintings is around 45%, which is slightly dry; humidity extremes should never exceed 30% to 70%. Moisture in the paper can attract atmospheric dirt, soot and acids, and will cause the colors of a finished painting to bleed.

The optimal temperatures for paper storage are around 60° to 65°F (15° to 18°C). High temperatures, especially as caused by direct sunlight, can significantly degrade paper. Warmer air can contain more water vapor at the same relative humidity, and heat increases chemical activity or the growth of mold in the paper. But strong temperature fluctuations, even in moderate temperature ranges, can have just as bad an effect. Again, keeping the paper wrapped and stored in the dark, or in flat files (see below), will alleviate extreme variations in temperature and humidity.

Dust is a common hazard, especially if it is darkened with soot or fine dirt, since the paper surface will trap particles deeply so that they cannot be easily brushed or washed away.

Air pollution is a significant and difficult problem in any urban area, but it even afflicts rural areas of the American northeast or southwest. Aerosols of dust or soot are a hazard. But worst of all is sulfuric acid or nitric acid, which can form in the paper when sulfur dioxide or nitrous oxide, created by emissions from power plants, factories, or cars, dissolves in the moisture already in the paper.

By a process called acid hydrolysis, this acid discolors the paper and breaks the long cellulose fibers into shorter fragments, making the paper brittle. Watercolor paper will absorb acid from the air even when the acid is present in very small amounts, and nothing you can do will get it out again -- paper only gets more acid with time. (Buffered papers are slightly alkaline and can neutralize small amounts of airborne acids, but prolonged exposure to air pollution will overwhelm even this defense.)

Watercolor paper is mostly cellulose, and contains substances such as gelatin or glue that insects enjoy eating; watercolor paints can add the spices of gum arabic and honey to the meal. The major predators are silverfish and sometimes cockroaches. You may notice these pests first in other parts of your house -- the kitchen or your bookshelves. If so, take extra precautions with your papers.

All these hazards can also afflict finished paintings. The best protection is to:

• frame finished works immediately, sealing the back of the frame completely and using ultraviolet shielding Plexiglas as a cover

• keep paintings hung away from direct sunlight or indirect sunlight from large windows; fluorescent lights are less of a hazard, but beware of prolonged exposure to bright lights or lamps of any kind

• hang the painting in areas with relatively small fluctuations in a moderate average temperature and humidity

• never store a painting in areas such as attics or basements where it may be exposed for prolonged periods to cold, damp, or insects.


paper hazards

handling papers

storing papers

mounting and framing

Damage to paper or paintings from any of these environmental hazards is irreversible and often irreparable. Take care.

handling papers

Although environmental hazards create a background of foreseeable and controllable dangers to paper, the single greatest hazard to a work on paper or unused art paper is ... human activity. Sylvie Turner mentions vandalism, theft, accidental burning, accidental staining (coffee, tea or milk, sir?), denting, folding, crushing, tearing, and so on.

The existential predicament is: you're a klutz, and damage to paper is almost always irreparable.

Most damage occurs when paper is handled or moved, so the first rule is to handle paper as little as possible. When you move sheets, always wash your hands first. (Besides being good to the paper, it's good for your hands).

Turner describes the use of "paper fingers," a strip of cardboard or paper folded in two and held between the thumb and fingers, to be used as pincers to grip the paper without touching it.

Leave stacks of paper in the original wrapping, and slide sheets out one at a time, from the top. Lift and hold a sheet at the opposite corners, with both hands, and carry it vertically so the paper does not shear in the air and bend or tear.

Always wash or wipe the surface where you will lay paper, including a workbench or stretching board. Many artists will use the wire side of a sheet if a painting started on the felt side goes south. It's annoying to turn a sheet over, expecting to salvage it by painting on the other side, only to find a large stain or blotch of dirt from the surface where it was laid.

Move slowly. You're painting, not bartending, so there's no rush. Think before you pick stuff up. Move containers and trays with both hands. Do not carry charged brushes a long distance over your work.

Go ahead and drink your coffee or Coke, just place it to one side of your work area, rather than next to the paper (where it can spill).

storing papers

I store watercolor blocks on a large bookshelf with the labeled edge out, just like my sketchbooks, and they seem as content with the treatment as any book would be.

For want of anything better, I keep single sheets of paper stacked flat, with stretching boards on top for added weight and insulation, on the bare hardwood floor under our queensize bed. It's cool, dry and dark there, and our enthusiastic housekeeper keeps the bugs and dust at bay, but it's far from optimal. (I just don't have the space for a studio.) I pull out a sheet when I need it, and order more when the stack gets small, always putting the old paper on top of any new paper ordered.

I've found it's sufficient to keep the paper in the original brown paper or plastic shipping wrapper, if the paper is used within a few months of purchase. But flat files or portfolios are safer for long term storage of papers or paintings, and also more convenient to use.

The really top end storage arrangements are wood or metal flat files. These generally run from about 36 inches wide and 24 inches deep (sufficient to hold imperial size paper or smaller), up to about 54 by 42 inches, which will take antiquarian size sheets, or two double elephant sheets laid side by side. The drawers are usually 2 to 3 inches deep, which will hold as many as 30 to 80 sheets, depending on weight.

Some retailers also offer stackable trays in the same size ranges as flat files. These have open fronts, so that you just slide paper in and out. Stored this way paper is easily accessible and largely safe from light, though humidity and homesteading spiders will have free access.

Portfolios. Once you've finished a painting, you can store it in a flat file or in a portfolio. Either method will protect the painting from light yet make it easy to get to for display or reference -- and you will learn a lot by periodically reviewing your old paintings! But the portfolio is really the thing to protect the work during personal transport. (Shipping the painting is another matter.)

Portfolios come in three basic styles. The simple polysleeve portfolio is made of two sheets of heavy plastic stitched on three sides, with a cutout handle on the fourth (open) side. These are sufficient for transporting a handful of smaller paintings (the stitched edge construction means the portfolio cannot expand to hold many sheets), but are not good for larger artworks.

The board portfolio is made of two flat boards wrapped in brown (or black) craft paper, joined with black cloth along a long edge with black cloth tie strips attached at the center of the other three edges to tie the boards together for transport. These are easy to use and provide good protection for large sheets carried on painting trips; they can also expand to hold as many as 20 or so full size sheets.

More elaborate is the presentation portfolio, basically a large black multiring binder, with plastic sleeves inserted and a zipper running around the three open edges; a handle and shoulder strap are attached to the outside of the binder. The plastic sleeves usually contain a sheet of black craft paper that act as a background and separator for art displayed on either side of the sleeve.

Stored flat, the presentation portfolio provides a completely lightproof and acid free storage for your best artworks. Flat files are the best for long term storage in general, and for organizing your art into different categories. The other portfolios provide excellent storage, provided they are stacked flat, out of light, just like exposed sheets of paper.

Large artwork stored in flat files or portfolios should be separated by tissue or glassine sheets to prevent the surface of a painting from being abraded by the back of the painting stacked on top of it. (This happens as you rifle through the stack looking for a particular painting.) Glassine comes in large rolls of varying widths, so you can tear off the size of sheet you need.

Make sure the drawers in files are made of plastic or painted metal. Bare metal may moisten and rust, staining the paper. Metal drawers tend to collect condensation. If this is a problem, include a small packet of calcium carbonate or other material to absorb excess moisture from the air.

Shipping. Occasionally you may need to ship artwork to galleries or clients, or transport papers during a move.

Art stored in flat files can usually be moved in them, provided the weight isn't unwieldy, the file drawers are secured so they won't slide open, and the sheets are separated with glassine so that they do not abrade during transport.

If you do not have flat files, wrap single sheets (in groups of no more than 20 or 30 sheets) in heavy plastic sheeting or brown craft paper. Do not wrap sheets into extremely heavy blocks, as the weight will damage the deckles during handling. (If you cannot lift the wrapped paper with one hand, it's too heavy.)

To ship one or more unframed paintings, first completely wrap each painting separately in plain brown paper, prominently labeled with your name and return address, then insert it between two sheets of masonite (1/8th inch thick is sufficient for imperial size sheets or smaller), about 1 inch larger on all sides than the paintings. Bind the masonite on all four edges with strapping tape or plastic wrapping tape. Label and ship.

Large framed paintings (larger than 3 feet on any side) should be crated. This normally entails sandwiching the painting between two heavy sheets of plywood, screwed to wood separators that seal the painting on all four sides. Styrofoam blocks, foam sheet or heavy paper packing is necessary to prevent damage to the frame and painting cover.

Unless you have carpentry skills or access to a compliant lumberyard, you will have to defer this task to a professional framing shop, gallery or art transport company. Your local art retailer can provide referrals.

mounting and framing

You will hear often from artists that framing a painting greatly improves its presentation. And this is usually true: a good frame can really make a painting sing.

But framing also significantly helps preserve the painting and protect it from the ravages of moisture, air pollution, harsh light, dirt, and mishandling that can cause warping, scraping or tearing.

Gottsegen gives the most detailed overview of matting and framing works on paper. His treatment focuses mostly on defining terms and providing step by step instructions for specific techniques, such as mounting a painting in mats.

As with watercolor paper itself, it's important to use mat and backing boards that are acid free and dimensionally stable to changes in heat or moisture in the room where the art is displayed. Quality commercial art materials always meet these standards, so your primary task is consistently to buy reputable brands from good suppliers.

You'll need a mat cutter to cut crisp, straight outer edges and inner window bevels on the mat. These come in two versions: a handheld cutter that requires a metal straightedge to guide the blade, or a tabletop cutter that mounts the blade on a metal rail that infallibly guides the cut. There are mounting boards in a variety of weights, specified as the ply of the board (a ply is roughly equivalent to 1/16th of an inch, or 1.5 millimeters).

The mat boards are available in many textures and colors, thinner than mounting boards. A rectangular window (the edge beveled to show a border of the darker mat core) is usually cut into the mat to mask the edges of the finished painting. The painting is centered under this window, and sandwiched between the mat and mounting board.

The mail catalogs available from Cheap Joe's or Pearl Paint give a good overview of the tools and materials required to mount and frame your own work. Any good art retailer will happily advise you on the best selection of materials and methods, and some will host or refer you to workshops where you can learn the skills from a pro.

The matted painting is next set into a frame and usually covered with a sheet of glass or Plexiglas (clear plastic). Again, this is something covered more fully in art handbooks, but a few points are worth mentioning.

Plexiglas generates a charge of static electricity when it is handled or cleaned (wiped with a cloth) after the painting is mounted. This charge is strong enough to pull loose particles of pastel chalk or charcoal off the paper. The remedy is to use glass for smaller works, or (especially in larger works) to set the artwork inside a shadowbox frame that places it an inch or so behind the clear cover.

Cracks in glass covers should be repaired immediately. The crack permits air to reach the painting, and if the air contains acid or dirt, a hairline discoloration will appear on the painting.

The style of framing should complement the style of the artwork itself. Highly ornate frames seem thoroughly out of fashion, but simple gilded or metal frames are sometimes used. Natural wood frames, stained or varnished to alter the color, are most common. These can be expensive, depending on the type of wood and its thickness.

Usually wood provides a slightly flexible and forgiving framework for the glass or Plexiglas cover. Woods that are high in tannins or acids, such as redwood or cedar, should not be used for frames. They also tend to be brittle woods, and prone to cracking.

Trimming Deckles. In the 19th century and much of the 20th century, the deckles on watercolor papers were just imperfections remaining from the manufacture. Artists or dealers almost always cut them away from the finished painting.

That is convenient for artists who stretch papers, as almost every stretching method damages the deckles enough to make removing them preferable. Then the painting is mounted under a mat, as described above.

In contrast, the current style is to present the work on paper as a complete artifact, making all the material attributes of the work visible within the frame. This is done by floating the work on the mounting board and leaving the edges unmatted.

The work, centered in the frame, is fixed to a heavy archival quality mounting board or heavy mat by starch paste or two sided archival tape applied at all four corners and a minimal number of spots along the edges of the work. The backing is larger than the painting by three or four inches on all sides, so the piece seems to "float" on top of the backing. The deckle and any warping in the paper are left to view as part of the finished work.

When the artist has taken care of the deckles, and has not blatantly damaged the painting with tacks or staples, the effect can be stunning. This large format Joseph Raffael watercolor, framed by the Nancy Hoffman Gallery, is typical of the style.

Preserving the deckles means that the watercolor paper cannot be stretched with paper tape, as the painting is usually cut along the tape edges (inside the deckles) to free it from the board. Securing the unstretched sheet with large paper clamps, or stretching it using staples and tongue depressors, are the better choices.

Flattening a Painting. Floating the work also makes flattening the painting less desirable, unless successive washes or soakings have really warped the sheet to where the surface and not the image is the first thing a viewer will notice.

Charles LeClair gives the most detailed instructions for flattening a finished work. The procedure is not complicated but it must be done carefully to keep water from wetting the painting itself. (You may want to practice first on a discarded painting, to make sure you know how much wetting is enough.)

• The necessary materials are: two terrycloth towels, larger in length and width than the painting; two sheets of heavy plywood, Plexiglas, masonite or particle board, larger than the painting; heavy objects (bricks, books, free weights) sufficient to create about 20 pounds of pressure per square foot of painting area; a misting or spray bottle of clear water.

• Lay the painting face down on a large kitchen counter, formica table or other flat, clean surface. Do not place any wicking material, such as a towel or newspaper, under the painting. Carefully moisten the back of the painting with a spray bottle until the paper is evenly wet. To spray along the edges, turn the spray outward (holding the bottle over the center of the painting) so that water is aimed away from the paper as it strikes the edge. Do not allow water to run back or puddle along the edges where it can wick under the paper and wet the painting itself. Lightly add water to areas that appear to have dried; do not create any pools or puddles. Wet the paper only until it loses its stiffness and holds an even, satin wetness for several seconds.

• Place one sheet of the plywood, Plexiglas or masonite board on the floor, in an area where it can sit undisturbed. Cover the board with a single terrycloth towel or printer's press felt. (Do not use towels with heavy seams or embossed designs such as monograms on them, as these can create indentations in the paper.)

• Carefully lift the painting: wipe away excess water that has pooled next to a corner edge, then slip your fingernail, palette knife or putty knife under the edge, grip the paper from the back with your thumb, and lift. Excess water may drip from the opposite corner; wick this from the back.

• Place the painting face down (damp side up) on the towel, then lay the second towel or press felt on top of the painting, and smooth out any wrinkles. Lay the second sheet of Plexiglas or masonite on top of the stack.

• Weight the upper sheet of Plexiglas with books, bricks, or any other massy, flat objects. Spread the weights evenly over the entire surface of the sheet to apply about 20 pounds of weight per square foot.

• Let the painting sit undisturbed two to five days (depending on the humidity and average temperature of your work area). Remove the weights and inspect the painting. If necessary, reassemble the stack to let the paper dry completely, or repeat the process to flatten it further.

The preferred alternative is to paint on paper stock heavy enough to resist serious warping under the methods you use. Some artists work in small areas with controlled, small applications of paint, and on standard (300 GSM) paper stock this produces minimal, consistent warping that is not at all distracting. Others apply juicy washes or glazes to large areas, and this usually requires a heavier watercolor paper stock, 400 GSM or more, to come out of the process relatively flat.