Pigment Powder, Sorting Particles With Water

I recently remembered a lesson taught to me by a friend who has experience purifying clay for pottery. Water can be used to sort the sizes of particles. Time is the factor that sorts them – larger particles settle first while the tiny particles that I want for ink will stay suspended for a long time.

So, I took a pigment that I had powdered and mixed it with water. I stirred it up and let it settle for 45 seconds before pouring the clearer water with the smaller particles still suspended into the second container. There are no photos of that process because my hands were very busy.

[Smaller particles to the left, larger particles to the right]

A while later, the particles in both containers had settled down to the bottom, leaving clear water that I would be able to pour off.

[Closeup of the larger particles after settling]
[Closeup of the smaller particles, more settling required]
The smaller particles had to settle overnight before they were ready to use. I was finally able to pour off most of the water, leaving just the particles with little enough moisture that I could just wait for it to evaporate.

[Pouring off the clear water]
As it evaporated, I kept an eye on it. When the particle slurry was thick enough, I turned the cup around every once in a while to keep the inside coated. This greatly increases the surface area, allowing it to dry much faster.

[Coating the inside of the container]

[Container coated and ready to dry]
[The completely dried coating]

From start to finish, it took over two days for this little cup of pigment powder to settle and dry. In the end, I got a very small amount of pigment with particles small enough to use in ink. In the future, I’ll have to find ways to grind more powder at once or dry it faster in order to keep up with the amount that I’ll need in the printing studio.

[Dried pigment scraped from the container and stored]

I can’t wait to mix this pigment with an ink base and see what kind of color density I can get from it.

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