Everything You Need to Know About Granulating and Duochrome Watercolours

December 19, 2025 ondine de peretti

In this article, I talk about two types of watercolours that I use a lot to give character to my paintings: granulating colours and duochrome colours. I discuss them together because they have similar properties and there are a few tips you need to know to use them and get the best results.

What Are Granulating and Duochrome Watercolours?

Granulating Watercolour: Definition

Granulating colours are those whose pigments clump together on the surface of the paper as they dry. They create textures, which is called granulation, unlike regular watercolours, which have a smooth finish. This characteristic comes from the type of pigment: cobalt, ultramarine, cerulean, oxide, etc., are known for granulating. These shades are often identified on the packaging with a "G" (show an example). They are sometimes grouped in sets, such as "Granulating Colours" by Winsor & Newton or "PrimaTek" by Daniel Smith, created from minerals.

The artisanal watercolour makers Les Couleurs VF, who focus on offering unique and characterful colours, offer many granulating shades, always identified as such in their descriptions.

Colour chart Les Couleurs VF:on the left, classic smooth colours (Litchi, Impatiente, Abricot, Renoncule, Prune, Flamand rose, Bourgeon, Nuit d'orage, Capucine, Boule de gui), and on the right, granulating colours (Rose pourdré, Grue cendrée, Figue, Écorce, Myosotis, Nuit profonde, Hellébore, Mer de glace, Agapanthe, Sauge)

Duochrome Watercolour: Definition

Duochromes are composed of at least two pigments, with at least one that granulates. These pigments behave differently as the paper dries: one is generally heavier than the other, one migrates more or less than the other. As the paper dries, these pigments separate on the sheet, creating surprising nuances and effects.

Few major watercolour brands offer duochromes; Schmincke, for example, created five "Super Granulating" sets. Again, Les Couleurs VF expertly combine pigments to produce deep duochrome colours.

Colour chart Les Couleurs VF: Céladon, Prunelle, Volubilis, Chrysanthème, Juliette, Chèvrefeuille, Ipomée, Rivière, Euphorbe, Aster.

If you have granulating colours, you can create duochrome effects by mixing them, achieving the effects of duochrome watercolours.

Mixes with Sennelier colours: Sennelier Orange + Caput Mortum (G) / Primary Yellow + Cobalt green (G) / Cobalt violet light hue + Cobalt green (G)

What About Granulation Medium?

I haven’t tested many, and I wasn’t convinced. I think you can’t force granulation in a colour that naturally behaves smoothly, and it complicates painting and wash management. Some watercolourists have tried them, but no one has found a revolutionary medium yet. So if you want granulations, it’s better to buy one or two granulating colours and use them for mixes.

How to Bring Out the Granulating and Duochrome Effects

Use Textured Paper

To reveal granulation, it’s best to use paper with a pronounced texture so pigments settle in the paper’s grooves. This works well with cold-pressed and rough papers (see my paper recommendations in my watercolour materials article). Some colours granulate a lot, others less, and rough paper will highlight these effects. Also, the larger the area, the more visible the effect and variations.

Use Plenty of Water and Let Pigments Move

Granulating watercolours rely on pigments moving and clumping in water while the paper is wet. Give them space and time to move freely, using plenty of water and washes. This works well for gradients, blends, soft-focus areas, or wet-on-wet techniques. Drying time is important because it gradually enhances the effects. Avoid using a hairdryer, as the airflow breaks the granulation and diminishes the effect.

Top: small surface, very fine paper, little water / Bottom: larger surface, heavily textured paper, plenty of water

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Influencing Duochrome Effects

You can play with the fact that duochrome pigments behave differently. In a wet area, the heavier pigments settle while the lighter ones remain longer on the surface. You can remove some wash by wiping the brush to better reveal the heavier pigment, or add water to spread surface pigments. Experiment: tilt your paper or blow on it to move the pigments—they won’t behave the same, enhancing the separation effects. I demonstrate all these techniques in my YouTube video on the subject.

Note: Salt or water bloom effects don’t work well with these watercolours because the heavy, clumped pigments no longer move, while these effects rely on moving pigments.

Watch my YouTube video for a full demonstration of using these watercolours.

Where and How to Use Granulating and Duochrome Watercolours

You can do a monochrome with a granulating or duochrome colour for a very specific mood.

If you want to integrate these watercolours into a palette, I recommend using them in specific areas of your painting. Like using salt or adding fine details, they should be applied only in certain zones, especially where you want to draw the viewer’s eye.

In a landscape, these watercolours add character and work particularly well for mountains or stormy clouds. They also break the monotony of a sky or add depth to vegetated areas.