What is a granulating paint?

So we have talked about paper and the significance of understanding how the type of paper influences the effects we see in granulated paint.

Let’s talk about the causes behind the properties of granulating paint.

According to the dictionary; Granulate means; “form (something) into grains or particles.”

Where watercolor paint is concerned, it means;

1. Heavy pigment particles that settle into the paper indentations.

2. Light pigment particles settle together due to attraction. (often referred to as flocculation)

Generally, the rule of thumb applies that the denser (heavier) the pigment particles, the more likely it is to granulate.

Essentially this means that it really boils down to using specific pigment types because not all pigments are the same in their densities and due to this, we have pigments that granulate and pigments that do not.

So, if it is only the type of pigment that causes granulation to happen then this poses two questions.

1. What are these pigment types?

2. Why do I appear to have a granulated effect with pigments not deemed traditionally granulated? Or why do I get a granulated effect when I mix random colors together on my paper?

What are the pigment types?

These are usually the pigments that are not as finely milled. Some brands may finely mill their pigments so that they do not granulate or they are mulled for a longer duration of time which leads to reduction in pigment particle size.

Ultramarines. Some ultramarines can vary between brands such as Ultramarine Pink.

Cobalt’s. This includes Cerulean blue as well.

Earth tones. This is also dependent upon whether the pigment is synthetic rather than natural. Generally the natural earth pigments have dramatic granulating effects. Also, don't forget Potter's Pink and Caput Mortuum. Most oxide pigments too!

Some backs. Black iron oxide is the most granulating of blacks. Lamp Black does not generally granulate.

Gemstones. These are made from stones and vary depending on how they are processed. I have worked with pigments that are much coarser and this leads to a dramatic granulated effect.

Why do I appear to have a granulated effect with pigments not deemed traditionally granulated? Or why do I get a granulated effect when I mix random colors together on my paper?

This effect is often mistaken for a different scientific phenomenon called flocculation.

Flocculation is difficult to spot unless you understand what causes it.

Flocculation occurs when pigments become electrically charged or attracted to one another and have the tendency to clump together. When they clump together on the paper, they cause the appearance of granulation. This is how a color that does not normally granulate can appear to.

So, granulation is the appearance of visible particles of pigment on the paper due to the uneven settling of the sediment.

Flocculation is the mutual attraction of small particles of pigment into groups that create ‘patterns’ on the paper.

So, because the two processes of causation are different, this deems each a unique phenomenon.

There is very little information and research conducted on both of these effects, especially flocculation but it is possible to tell the difference visually.

Here are images below that show you examples of flocculation:

Images credit to https://rachelarmington.com/painting-lessons/lovely-flocculation-and-granulation/

Here are images below that show you examples of granulation:

All four images are examples of a granulating paint whereby the pigment particles have settled into the watercolor paper indentations.

The effect is often a bit more consistent in appearance than the effect of flocculation where it is more a random occurrence of mutually attracted pigment particles.

Some argue that flocculation is a "subset" of granulation itself.

(Paper used here is coldpress Arches/Bockingford)

I hope you enjoyed reading this article. Let me know your thoughts or questions that you might have around this topic.

What topic are you interested in next?

Stacey x