Painting Simulator

A painting tool that goes out of its way to be difficult. It mixes pigments the way paint actually mixes, presses harder when you move slowly, runs out of paint mid-stroke, drags wet paint into wet paint, and remembers what colour was on the brush the last time you dipped it. Each of these inconveniences has its own off switch; turn them all off and you are back to drawing ordinary uniform lines, which is the point.

• Colors mix with two-constant Kubelka-Munk optics on 8 spectral bands, so blue and yellow make green instead of gray.
• Pressure is estimated from cursor speed: slow strokes press hard and lay down wet paint, fast strokes barely touch the paper.
• The brush holds a finite charge and dries out over a long stroke, the paper has tooth that a dry brush skips over, and fresh paint smears into strokes that have not dried yet.
• The pigment data are hand-tuned plausible spectra, not measurements; the physics is honest, the numbers are invented.