The allure and exclusivity of watercolour lies within the pigments properties, each containing characteristics not found in any other painting medium. The colours visually appear transparent and gleam on the paper, while others deposit sediment into the hills and valleys of your paper, giving a textured feel.
Watercolour paints are made from either natural pigments found in the earth; clay, minerals..., and from synthetic pigments, which have been finely ground down and then held together with a water-soluble based “gum” binder; like Gum Arabic, Honey or QoR revolutionary binder Aquazol.
Watercolour paints are available in two forms; tube and pan, with tube being the most popular.
Watercolour Pigment Characteristics
Transparency: All pigments are relatively transparent or opaque. The colour charts distinguish colours as ‘Transparent (T) or Semi-transparent’ (S) or – ‘Opaque (O) or Semi – opaque’ (SO). It’s important to remember that transparency is relative and the tables are a guide only.
As watercolour films are so thin, all colours appear more or less transparent when painted onto paper. Opaque colours, like Cadmiums, will however, cover a little more than transparent colours. Titanium White [Opaque White] can be added to all colours to increase opacity, but will of course reduce those colours to tints.
Granulation: In watercolour, some colours show a tendency to granulate and are shown on the colour charts by the letter ‘G’. Granulation adds visual texture by the pigment particles settling in the hollows of the paper, producing a mottled effect. As a general statement the traditional pigments granulate, eg. cobalts, earths, ultramarine. The modern organic pigments do not, eg. quinacridones, arylamides, benzimidazolones. These colours are often under common names like ‘Winsor’ or ‘Permanent’. If you wish to avoid granulation in your painting, the use of distilled water can reduce it in very hard water areas. if one wishes to add more granulation, there is a medium that can add granulation of non granulated pigments or add more granulated textures to a granulated pigment colour.
Staining: The modern organic colours are made from very fine particles which cause them to stain the paper. These colours cannot be lifted completely with a damp sponge and are shown on the colour charts by ‘S’. Staining colours give high value images but do not easily allow for reworking. Staining in watercolour should not be confused with bleeding of any dye – based colours in Designers’ Gouache.
Permanence With the introduction of new pigments, the permanence of watercolours has been greatly improved in comparison to the past. The belief that watercolours are less permanent than oils is no longer the case. There are now 88 AA or A rated colours in Artists’ Watercolour.