Some watercolours sit on the paper and lift away cleanly with a wet brush; others sink in and stain the paper so deeply that no amount of lifting will shift them. Knowing which of your colours stain - and which do not - governs how you layer, correct and finish a painting.
What makes a pigment staining
Staining is a property of the pigment's chemistry and particle size. Very fine, synthetic pigments - the phthalocyanines, the quinacridones, the dioxazines - are small enough to penetrate the paper fibres and bind to them, so they stain. Coarser, earthier pigments - the iron oxides, ultramarine, many traditional lakes - sit on the surface and lift more readily.
Staining vs non-staining behaviour
A staining pigment (Phthalo Blue PB15, Quinacridone Rose PV19) goes down vividly, tints powerfully in mixes, and resists lifting - you can soften an edge but you will not lift the colour back to white. A non-staining pigment (Ultramarine PB29, Burnt Sienna PBr7) can be re-wetted and lifted, blotted, or scrubbed back to recover the paper.
Lifting and reworking
For work that you want to correct, lift or rework - portraits, detailed botanicals, anything with recovered highlights - choose non-staining pigments and a paper that forgives. For vivid, permanent underpainting that will not move when you glaze over it, choose staining pigments as your first layer.
Layering strategies
- Staining under, lifting over - lay a staining wash first so later glazes do not disturb it.
- Non-staining for recoverable passages - keep your options open where you may want to lift.
- Mind the mix - one staining pigment in a mix will make the whole mix harder to lift.
Choosing staining pigments for vibrancy
Staining pigments give the most intense, saturated colour watercolour can offer - a little goes a long way. Explore them in the watercolour range, test mixes in the Mixing Studio, and see the full palette in the watercolour swatch library.