Sunday, June 1, 2008

Improved Slurry Technique to Try

My wife is into knitting, spinning, and all things fabric.
Guess who I'm going to enlist to help me make a canvas from scratch? :)

She was talking with Michael Cook online recently about my project, and he suggested another technique for refining earth pigments. Michael has a very cool project of his own going on. Check out

Anyway, here's the full text of his technique. I'm hoping to try this out in a couple of weeks:

I asked Alyssa if you were levigating the pigments - and I figured I'd
reply to you instead of making her play messenger!

What I was doing, was grinding the rocks (mostly yellow and red
ochres, but also malachite and some whitish chalks) to a fine powder -
starting with a hammer and a pillow case, and ending up with a
dedicated coffee grinder. I would put that into a jar with water, and
swirl it vigorously to mix. The liquor of color would be on top, and
the grit would quickly settle out. I poured the liquor of color off
into a shallow bowl, and let it dry, which made a fine, usually
grit-free powder. If the powder still felt gritty after levigating it
once, I repeated, and then mulled the resulting powder with water
using a glass muller and a glass plate, then let it dry for storage or
mix directly with binder. I did a little paint-sketching with them,
although it was all just samples and I didn't keep a completed

Couple of things to think about for this project:

This technique might be a lot faster than me letting the particles settle down, then have the entire jar of mud dry. And, it should give me a more consistent and finer particle.

How do I make a glass muller (or any muller for that matter) from scratch? Maybe a clay/ceramic fired one with a good glaze? Or maybe an especially smooth & flat skipping stone?

If I implement both this technique & the use of a muller, I'm hoping to get a nearly commercial grade of pigment. I'll post the results as I try this out!

Cheers, and keep the suggestions coming!