How to Prevent Watercolor Paper from Curling
As a watercolor artist I have felt the frustration that can rise up when, after hours of careful work, the paper I have slaved over begins to buckle and curl. I have found several ways to avoid this problem over the years.
The most traditional and time honored of these methods is to stretch the paper on a rigid surface (masonite drawing board, gator board, etc.). This is done by soaking the paper in water to thoroughly relax the fibers in the paper. Then the paper is placed on the surface and taped or stapled in place. I have always used paper package sealing tape that has an adhesive that becomes activated by wetting the glue on one side. The paper is then allowed to dry completely. As the paper dries, the fibers tighten within the paper and stretch to an extremely taut surface, almost like the skin of a drum. This stretching holds the paper in place and water and washes can be applied to it without it resulting in buckling or curling. This method can be frustrating because sometimes the tape does not hold completely and the stretching process can result in buckled paper from the get-go. One great benefit of this method is that the artist can stretch paper in whatever dimensions he or she desires. The other methods I'm going to describe later require the artist to work in the dimensions predetermined by art supply manufacturers. Another plus to this method is that the artist is free to use lighter weight (thus cheaper) paper and still get a good, smooth result.
I should mention here that one way to avoid the problem of buckling and curling watercolor paper is to buy a really heavy weight paper (300 lb +). This is a solution that I don't frequently use, because to me the cost of the paper is prohibitive. However, this is the most straightforward solution to the problem. If the cost is something that is not an issue for you, this is the easiest way ensure your paper will not warp.
Another almost fool-proof way to prevent watercolor paper from buckling and curling is to work on a watercolor block. This is a pad of watercolor paper that has each sheet glued in place on all four sides with just a little opening in one side. Each sheet is thereby "stretched" and ready to have paint applied with no additional effort on the artist's part necessary to prevent warping. This is a more affordable way to preserve the smoothness of the paper than the heavy watercolor paper, and it is much easier and reliable than stretching the paper in the way mentioned above. Much of my work is done on watercolor blocks. They come in various sizes and styles of paper. Just a note to mention that watercolor paper comes in several types of surface: cold press, hot press, and rough. Each surface has its benefits and characteristics. It's best for an artist to experiment with each type of paper to see which fits his or her style and objectives. Once the painting on the watercolor block is completed and thoroughly dry, the artist simply carefully cuts the finished painting off the top of the block using an exacto knife and the next sheet is revealed and ready for the upcoming masterpiece! The small opening in the glue surrounding the watercolor block is designed to be the place where the artist can start the cut to remove the top sheet once the painting is completed.
The last method for keeping watercolor paper in good shape when applying washes is the watercolor board. This is a relatively new invention, and it is great for allowing artists to use light-weight papers and still use very highly liquid washes without dire consequences to the integrity of the paper. The board consists of a wooden panel with a metal frame around the perimeter. The board works similarly to the paper stretching method I described earlier. Instead of stapling or taping the wet paper to the board, the paper is fastened through the use of the screws spaced around the metal frame (see picture). I have never had a failure when stretching my paper with the watercolor board. My board is large, accommodating a full sheet of watercolor paper. This is my "go to" paper stretching method when I want to create a large painting.
I purchased my board several years ago for about $120. The WatercolorBoard is available at Judsonsart.com.
There are many solutions to the problem of keeping watercolor paper unruffled by the abuse we artists heap on it in the pursuit of our masterpieces. Some of these solutions are more expensive and demanding than others. My experience has taught me that all of the methods I have described in this hub can be successful, and I use them all. It is up to each individual artist to determine which of these methods work best for them. My suggestion is to try a variety of these methods and see which is most comfortable for you.