Unit
- Paper types: Watercolor paper comes in three main surfaces: hot press (smooth, for detail), cold press (slight texture, all-purpose), and rough (heavy texture, for effects). Each surface affects how paint flows and dries.
- Weight matters: Paper weight indicates thickness, measured in pounds (lb) or grams per square meter (gsm). 140 lb (300 gsm) is standard; lighter paper buckles, heavier paper (300 lb) stays flat without stretching.
- Sizing: Paper is sized with gelatin or synthetic to control absorbency. Too much sizing causes paint to sit on top; too little results in rapid soaking and loss of color vibrancy.
- Stretching paper: For thin paper (90 lb or less), stretch it by soaking and taping to a board to prevent buckling when wet. Soak for 5 minutes, then tape edges firmly.
- Cotton vs wood pulp: Cotton paper (100% cotton) is durable, holds more water, and allows lifting; wood pulp paper is cheaper but less forgiving. Artists prefer cotton for permanence.
- Blocks vs sheets: Paper comes in blocks (glued on all edges, no stretching needed) or individual sheets. Blocks are convenient for plein air; sheets offer flexibility for large works.
- Brightness and acidity: Acid-free paper prevents yellowing over time. Brightness affects color perception; a bright white paper makes colors appear more vivid.
- Testing before buying: Purchase sample packs to test paper with your techniques. Different brands have different sizing and texture, so find one that suits your style.
Design Principle
Principle: Paper Surface and Wash Control
Definition: The texture of paper directly influences how watercolor washes behave. Smooth paper (hot press) allows crisp edges and even washes but dries quickly; rough paper holds more water in its valleys, creating granulation and uneven edges.
Application: For a sky wash with soft clouds, use cold press paper: its tooth holds enough water to blend gradually. For detailed botanical illustrations, choose hot press to keep edges sharp and colors flat.
Quick Revision
- Select paper based on surface texture, weight, and sizing.
- Hot press for detail, cold press for general use, rough for texture effects.
- Standard weight is 140 lb; stretch thin paper to avoid buckling.
- Cotton paper offers best performance and longevity.
- Test different brands to find your preferred surface.