Watercolor paper is a large investment. It is expensive. You do not want to make avoidable mistakes by purchasing the wrong paper. Save money and frustration by reviewing the following list of watercolor paper properties and bonus tips to determine which paper meets your needs. (Note: I am not a representative of any paper company, just an experienced watercolor artist and research analyst.)
1. Manufacturer Reputation. Some papers which are favored by professional artists include brands by Arches, Saunders Waterford, Fabiano, and Legion Stonehenge. Also, there are specialty handmade papers but be sure to purchase these from reputable long-time manufactures or you may end up with rust dots and other problems. Therefore, I suggest you try out a handmade paper by Twinrocker. Do not use a manufacturers’ student paper. I suggest that you purchase paper samples to test how the paper behaves with your watercolor paint and techniques.
2. Form. Forget about using watercolor tablets/pads, blocks because they do not have the same qualities as the full-sheet or roll papers. Do yourself a favor and stick to full sheets (22 x 30 inches—called Imperial size) or rolls of professional watercolor paper. You can fold and tear them to the size you need. I say “tear” them because you will want deckled edges. Also, this may be a cheaper alternative then purchasing tablets and blocks. Even students should use professional paper because they will not experience how their newly learned techniques can perform on student grade paper.
3. Process. The paper can be handmade, mold-made, or machine-made. Machine-made paper is less costly than the others. However, the regular pattern of the paper is not desired by many artists. This does not matter on hot press (smooth) paper.
4. Content. The paper should be 100% cotton (all rag paper), linen, hemp, or a combination. Even here, there are different qualities of cotton used by varying manufacturers.
5. Sizing. Know that 100% cotton paper also contains sizing. Sizing (usually gelatin) is added to the pulp. But the best brands add sizing to the front or both front and back. Also, a fungicide is added to some brands. Artists should know how the paper is sized. For instance, you will want to ensure that you paint on the front of the paper if it is only sized on the front because the paints will quickly soak through the paper on the unsized back leaving a dull look to the final painting…and making paint manipulation difficult. Heavily-sized watercolor paper sometimes makes it difficult to get the watercolor too lay down on the paper, unless the paper has been soaked. However, colors appear brighter on a heavily-sized paper.
6. Weight. Watercolor paper comes in various weights, but I believe that best weight is 140 pound. It does warp at that weight if you are using large washes of watercolor and water. However, the color does not sink into the paper as much as it will with 300 lb. paper. Also, you will see a richer look to your painting.
7. Texture. The basic textures available include: Cold pressed, hot pressed, and rough. Artists use different types of paper depending on their subject matter. For instance, many artists prefer rough paper when working on landscapes because of the texture it provides. Hot press paper is smooth and basically shows every brushstroke. Cold press paper (also called “not” paper) is a texture in between.
8. Color. Manufacturers’ color lists include: White, bright white, natural, etc. With today’s acceptance of white gouache on watercolor paper, it is okay to paint white gouache on a watercolor painting (likely needed if your paper is tinted). However, with gouache paint it now becomes a watercolor and gouache painting.
9. Paper support. (Bonus Tip 1) You must use the correct support when painting watercolor. Never use an absorbent support like wood or cardboard. I suggest a “board” manufactured for watercolors, PVC foam board (easy to cut to size), or glass (not mobile). It is great that if you use a frame with an open back you can dry a wet painting from the back without spreading any wet paint on the surface or pushing the paint particles deeper into the paper.
10. Stretching paper. (Bonus Tip 2) If you want to paint on paper that does not warp, you can either use 300 lb. (or heavier) watercolor paper. Or stretch the thinner paper. This can be accomplished by using clips on your watercolor board. You can move the clips as the paper expands. Additional options are a professional frame that stretches watercolor paper, stapling watercolor paper to a wooden frame, or soaking paper then using gum tape to keep the paper stretched. If you keep the paper wet on a non-absorbent surface, the paper will stick to the board—but the paper must remain wet. Using a paper that has sizing on the back facilitates this process. Note that soaking the paper (in a tub, spraying, or wet brush) will remove some of the sizing which will impact how paint goes onto the paper. There are methods of flattening dried paper like placing weights on top of the dried painting, ironing (no steam), etc.