Pigment: Real Watercolour

Mix blue and yellow in almost any painting app and you get grey. That is not a taste problem, it is arithmetic: those apps average two RGB values, and averaging is not what paint does.

Pigment does what paint does. Every colour in the box is a named pigment with a measured absorption and a measured scattering strength, added together by mass the way two real paints combine in one puddle. Ultramarine and Hansa Yellow make a soft olive green because that is what the numbers say, not because somebody typed a green in.

WATER IS HALF THE BRUSH
Under the canvas is a shallow water simulation. Water runs downhill and wicks sideways into dry paper, faster into the low ground of the tooth than over the high. It leaves faster at the rim of a wash than in the middle, which drags colour outward and leaves the hard dark edge every painter recognises. Pigment travels with the water but slightly slower, so the wet edge always arrives before the colour does.

Drop clean water into a wash that has just lost its shine and the fresh water lifts what was settling and pushes it into a ragged rim. That is a backrun. There is no button to prevent it.

The water slider is the real instrument. Dry lays almost neat pigment and skips over the tooth. Wet lays a wash you can barely see.

TWENTY FOUR PIGMENTS THAT BEHAVE DIFFERENTLY
Ultramarine granulates into the valleys of cold press and lifts back off with a damp brush. Phthalo Blue never granulates, never lifts, and takes over any mix. Goethite is coarse natural iron ore, and a wash of it dries as a map of the paper. Granulation, staining, opacity and liftability are printed on the side of a real tube; here they are numbers the engine reads.

PAPER IS A DECISION
Cold press has tooth you can feel and collects granulating pigment in its low ground. Hot press lets washes slide and keeps every hard edge. Student cartridge drinks a wash before you have finished laying it, and buckles when soaked, which changes how the next wash pools.

EIGHT BRUSHES AND FIVE THINGS ON THEM
A mop, two rounds, a flat wash, an angled flat, a rigger, a fan and a sponge, every one of them running out of paint along the stroke the way a real brush does. Beyond paint there is clean water, a thirsty brush for lifting colour back out, masking fluid, and a hairdryer for drying where you point it.

THE MIXING WELL
A ceramic palette with real paint on it. Tap to squeeze a gob, drag to smear two together, and take the result away as a tube of your own. The smear is the same arithmetic the paper uses.

YOUR PROCESS IS THE FILE
A painting is not stored as an image. It is the log of every stroke: which brush, which paint, how much water, and the milliseconds between the points. Reopening a sheet replays the whole thing through the simulation. A painting of seventy strokes is about twenty kilobytes of stroke log.

That same log is the timelapse. Recording plays your strokes back through the physics and hands you a WebM video of the painting happening.

SIX GUIDED WASHES
A flat wash, a graded wash, wet into wet, the backrun, drybrush and lifting out. Each is a few minutes about water rather than about drawing.

HONEST ABOUT WHAT IT IS NOT
No gouache or oil engine. No layers. No community gallery, because that needs a server and this app has no network. Timelapse is WebM rather than MP4, because an MP4 encoder is not something an offline app can honestly claim. The simulation runs on the phone's processor, so a large sheet on an old phone runs the water more slowly. A stylus reports real pressure; a finger works too but its pressure is assumed rather than measured.

YOURS ALONE
Pigment does not request the internet permission, so Android will not let it open a connection at all. No account, no cloud, no analytics, no advertising ID, no crash reporter. Everything lives in this phone's private storage.

Every pigment, paper and brush is unlocked from the first launch. No subscription, no in app purchase, no advertising.

Paint that behaves.

Recent changes:
A new face. The launcher icon and the first screen are now the same wet into wet bloom, painted by the engine that paints your sheet, and finished sheets sit taped down in the drawer.

Fixed: in a guided wash the instruction card no longer sits on the paper, so the band it asks for actually lands. Taking a mix puts it on the brush and hands the sheet back. Recording a timelapse shows its progress and can be stopped. A double tap no longer stretches two sheets.