Ochre Refinement Part II

Over the weekend, the ochre finally dried again, and I had a chance to scratch away the last of the rough particles.



Drying. Still moist, but cracks have formed. Ever notice how mud cracks are always 3 lines at an intersection? Never 4 or 5? There's a reason for it (path of least resistance, conservation of energy, something like that) , but I don't know the details. Have them? Tell me!



Here, a couple of the pieces are flipped to show the sandy bottom. This part was scratched off with a putty knife, leaving only the finer pigment particles.


An example of the raw dirt & the dirt after it's been refined via a slurry twice.


Here is a disappointing image: When mixed with walnut oil, it is very close to the normal umber that I got from my parent's regular soil (the kind that doesn't require heavy digging to get to it). It's a tiny bit lighter and more yellow, but not nearly as much so as when it is in powder form.


There's a bigger difference between it & the burnt umber though :)

I'm going to try using this pigment in a tempra (egg whites) medium and see how it looks when it dries next. If that doesn't work, then I question it if will be worth using it along with the other two tones. It's just not yellow enough like this, and not worth digging deep to get to it :(

Ochre Refinement

I'm going to go out on a limb & call this stuff ochre. It's dirt, and it's yellowish. Close enough for me right now. It also drys my hands out much like Burning Man Playa dust, so I wonder if it is an alkaline... I might test that out with vinegar to see if it bubbles. If so, maybe I should neutralize it before using it on a painting.

I got tired of waiting for the slurry to dry, so I scooped out the good stuff with a putty knife & spread it on paper towels so it would dry faster. I figured this would be OK, because I was planning on doing two slurrys to get the best of the best.

When it's wet, it gets really dark and brownish. The brown piece between the putt knife & the dried ochre is what a moment prior was dry ochre, but sucked up some moisture from the wet ochre on the left. This makes me think it's not going to mix with walnut oil well. I'm guessing it will work better in egg yolk. I'll have to try them out side by side and see what happens.



On the left is the silt that I scooped out & on the right is all the sand & coarse dirt. I'd guess the proportion is about 1/8 silt.



Before crushing



After



This much pigment came from about 1/4 pound of dirt. I then took all of this, and mixed it in water again (not pictured). I was surprised to see a fair amount of sand separate out to the bottom! I'll update with final pigment & tests in a few more days. It will have to dry (not get scooped out) this time so I can scratch off the coarse particles more carefully. That takes about a week.

Back to Earth

I visited my parent's house two weekends ago, and found yet another earth pigment! My dad had dug a very deep hole with his excavator, in hopes that he could make an artificial pond. No such luck. But what he thinks might be sandstone (too soft for it in my opinion) I think might be related to ochre.








Here's a couple of comparison shots between the three tones I've found on his land so far. The brown/red is his normal soil, the reddest sample is that same soil after a bonfire has taken place on top of it, and the yellow/ochre is in his orchard, starting at about 4 feet deep in pockets, and showing up as deep as the 12' or so hole that he dug.





By the way, I was able to see different colors in this sample, like sedimentary layers. Maybe in a few thousand years, it would become a sedimentary rock.

Here's what it looks like in a standard slurry test (my attempt to get the fine particles separated out from the coarse ones with water. It settled in under an hour, very, very fast for such a test!). There's a lot of sand in there. I crushed it first in my mortar, and I think the crushing might have affected the color a bit. It's redder now. We'll see how it handles when it dries.