For most beginners, granulating paints are an unfamiliar concept. They are hardly colors that you are looking for and they are almost never included in ready-made watercolor boxes. In addition, they are often more expensive than other colors and in cheap color series they are usually replaced by other, less expensive pigments, sometimes with the name retained. You should not be sure that if you buy Cobalt Blue or Viridian that you will get these colors. If the color is cheap, some other dye has replaced these expensive pigments, even though they are still called Cobalt Blue and Viridian.
Pigment is an insoluble dye that is ground into a fine powder, the degree of grinding is different for different pigments, depending on lightfastness versus transparency. It’s a fine trade-off that paint manufacturers must consider. If you grind a certain pigment too fine, it loses durability but gains transparency, and vice versa.
There are two different types of granulating paints. Those that create a pattern because the pigment quickly sinks to the bottom because it is heavy. Another type is pigments that create patterns by clumping the pigment grains together.
Some pigments are heavy, the pigment grains do not float in the water. They quickly sink into a freshly painted paint surface and find all the small irregularities in the paper, they collect in the small pits and thus form an uneven and slightly grainy surface. The result is an evenly distributed color with small darker spots next to a lighter surface. The effect is accentuated with fluid painting, if you were to paint dry this effect is reduced. Such colors are sedimenting.
Some examples of sedimenting watercolor paints
Some pigments are flocculating. This means that the pigment grains have a tendency to collect in larger clumps. Such paints are also usually called granulating because they do not produce a smooth paint surface. The result with flocculating colors ranges from a sandpaper-like surface to obvious threadiness or small dots. The pattern is further enhanced if you try to achieve blooms, such painting enhances the formation of threads and dots. The color surface with such colors, with clear flocking, is unevenly distributed on the paper.
Some examples of flocculating watercolor paints
Some pigments are both heavy and flocculent. Such colors give a very clear pattern on the paper. Both sedimenting and flocculating paints are collectively called granulating. No paint manufacturer uses a specific term for settling or flocculating paints, all are just granulating.
All serious watercolor paint manufacturers state whether a particular paint granulates or not. However, almost none indicate the degree of granulation. Some paints only leave a faint pattern, while others granulate heavily. This degree difference can be different for the same color from different manufacturers.
If you are really interested in such things, as the degree of granulation, I can recommend handprint.com, a website compiled by Bruce MacEvoy. It is a nightmare to navigate, but is a goldmine of information.
In this context, the section on colors, pigments and manufacturers is a great source of knowledge. You find it here. (Menu for different groups of colors can be found at the top of the page). Since a few years ago, the page is no longer updated. Therefore, the newest colors, and manufacturers, are not represented but it is still very comprehensive.
Here you can find almost all colors from pretty much all major manufacturers arranged by hue and pigment name. A color’s granulation is indicated on a scale from 0 to 3, where 0 means “not at all” and 3 is very clear granulation. You will find the column indicating the degree of granulation on the right (Fourth column of numbers).
Whether you like or hate that some colors granulate is a matter of taste. Personally, I like to use granulating colours, I like colors with character and a will of their own. Painting with granulating paints requires a different handling than with “ordinary paints”. In a future post I will describe how I paint with such colors.