Sumi-e
Paint with ink on rice paper. The brush is made of bristles that each hold their own ink, so a stroke goes from wet to dry as you move, splits into dry-brush streaks when you go fast, and pools when you hold still. Raw paper drinks the ink and blooms it into soft grey halos; sized paper keeps the edges crisp. As with real sumi-e, dry ink cannot be lifted again.
Painting tips
- Hold still to pool. Rest the brush and the ink keeps flowing into the paper, which is how bamboo joints and blots are made.
- Move fast for "flying white". A quick stroke with a half-dry brush leaves the paper showing through between the bristles (fēibái, 飛白), the most prized texture in ink painting.
- Press, then lift. A leaf is one gesture: touch with the tip, press to widen, lift away to a point. With a pen the brush follows your pressure; with a mouse, slow means heavy and fast means light.
- The five inks. Painters speak of five tones, from burnt black (焦) through thick, heavy and light to clear (清). Dark tip loading puts all three main tones in one brush, so a single stroke shades from black to grey, as on the bamboo stalk.
How it works
The brush is about 80 bristles spread over a teardrop-shaped footprint that grows with pressure. Each bristle carries its own water and carbon. It gives some away in proportion to the paper it sweeps (less when moving fast, more when standing still). As it dries, it only touches the high fibres of the paper, which breaks the stroke into streaks.
The paper runs the wicking model from the watercolour page. Water soaks in and creeps along the fibres by invasion percolation. Carbon particles are too coarse to keep up, so they travel at about 40% of the water's pace (as in the chromatography page). That leaves a dark core inside a pale grey halo. The animal glue in ink stick keeps pace with the water and dries as a faint tide line. Carbon that touches a fibre binds to it for good.
The papers are generated: grain, fibres, a holding capacity, and either laid lines or cracks. Their absorbency and the brush rates were tuned by eye against photographs of real sumi-e, not measured.