Water causes paper to shrink. For this reason, watercolor paper should be prepared in advance of painting in order to prevent buckling and wrinkling from interrupting brushstrokes, and to ensure the good appearance of the finished, framed artwork.

Watercolor papers contain sizing, a starch or glue that keeps pigment on the surface in a transparent glaze, allowing the white of the paper to reflect through, giving luminosity to colors. Watercolor paper should be pre-shrunk in preparation, and the sizing must be softened for this to occur. For lighter, 90lb. paper, a light sponging will suffice; 140lb requires heavy sponging or spraying. Papers 300lb and heavier may need to be briefly immersed in a bath of water to effectively wet them. After wetting, blot excess moisture with paper towels.

Paper should be attached to a rigid board to provide a good, flat surface. Hardboard panel or smooth plywood are fine, if sealed to resist water- a thick coat of varnish will seal boards well enough. Sheet acrylic and formica work well, also.

To attach paper to a sealed board, wide brown kraft tape is best. This must be the type with water-activated gum adhesive, not the self-adhesive variety. Moisten lengths of tape with a damp sponge, taking care not to wash away adhesive. Apply tape covering all four edges of the sheet completely, overlapping about 1 full inch (more is better, but will leave less working area). Allow to dry completely before painting. When the painting is finished and dry, cut along tape lines to remove from board (expect to lose some paper).

Self-adhesive tapes such as wide drafting tape can be used for mounting watercolor paper, but should only be used for lightweight papers. Self-adhesive tape allows complete removal, and will preserve deckle edges. Occasionally, however, moisture will loosen this variety during painting, creating a mild nuisance. For stretching with drafting tape, moisten paper with a sponge after paper is firmly taped to board, as this type of tape will not stick to wet paper.

Papers sold in block form are gummed on all sides to a thick book-board backing, and will wrinkle only minimally during painting. A small space is left in the gum on the edge tangent to where the cover is attached to facilitate removal of finished work. Insert a palette knife in the slot provided, and cut all the way around, separating the glue.

Some artists choose to sacrifice a bit more paper at the edges to achieve a very tight stretch by stapling paper to canvas stretchers. Apply water to paper as when fixing to a board; insert staples starting at the center of each side, working across to opposite sides, working toward the corners. Corners may be folded over for sake of tidiness, but this step is not technically necessary.

The moment you wish to begin painting is too late to begin stretching paper. Always having a sheet or two prepared is a good studio habit to acquire.

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