One of the pigment resources I use from the land around Wild Ozark is a dark gray shale. We’re located where a geological formation called Fayetteville Shale spreads beneath and around. Most people associate it with natural gas and oil. For me, it means a beautiful gray paint.
The process of turning shale to paint is the same as with the other stones. Except with this one, washing it is critical. Why? Because it stinks even as a paint while it’s wet if you don’t (the smell fades once it dries). But more importantly, the odorous compounds of sulfur could react over time with your paper or other pigments. And washing it removes the problems.
I find the shale either in the creek here on our land or in Felkins creek just a short distance from our mailbox.
It’s pretty crumbly and easy to break into smaller pieces. But reducing it to powder is more difficult. I could use the rock crusher to do this, but the powder is clingy and would be hard to clean out of the crusher.
When I crush a persistent pigment like that, I usually run a neutral colored sandstone through it afterwards. But in this case, I only need a pan of paint, not a whole lot of it, so mortar and pestle it is.
I washed even this small amount of powder twice. Fill the jar with hot water, shake, let settle a minute. Then pour off the water. In sandstones, I save the colored water to settle for a very fine pigment. But in the shale, I throw out all of the water once the heavier bits have settled, even though there’s color in it.
After the second wash, I transfer the sludge to a smaller jar that fits in my dehydrator. After it settles and the water on top has cleared, I’ll drain that off before putting it into the deyhydrator. Or, since it’s winter and the heaters are running, I may set it on top of the heater to dry.
I’ll post pics of the next stages as I get to them once the pigment is dry.
the supplies I used
Most of my items are things I’ve ordered from Amazon. I have an affiliate account with them, so the page at my shop where supplies are listed are linked to those products. You can get these things at most other places that sell art supplies, but I live too far from town and so mail order most of my things.
I’m hoping to soon have an account with other art supply companies, too.