Sunday, April 20, 2008

Two Pigment Tests in one day!

I felt especially productive this weekend, and Ravenna wanted to hang out with me in the garage, so I tried two new pigment tests. Both additions have made it into the header. Hey, anyone out there know how to make this header an image map using Google's Blogger? I'd really love to have each color link to their respective entries!

Pristine




First up is what I *think* is called ‘Pristine’. I got it from John Garsow when I bought a bunch of Lapis Lazuli from him. We were hoping it would make an OK white. I think it is some sort of magnesium oxide, but I couldn’t find anything on the web about it recently. I’ll send an update if I do. In the meantime, please comment if you recognize this rock/stone/mineral/thing.









The rock looks fairly white, with possibly a little rust or dirt on the outside. The powder looks great. However, when I mixed it with walnut oil, I got a light and somewhat grey. I’m thinking the grey came from one of four possible sources.









  1. The impurities in the rock

  2. The impurities from my mixing board

  3. A chemical reaction with the walnut oil (I can test this by trying this pigment out with a different medium)

  4. Some sort of reaction with my palette knife metal (I can try something else to
    mix the pigment & the medium together)


It’s not very opaque, so I think I’m going to keep looking for a better white (maybe go back to eggshells? I don’t know)


Jasper



Second up is some Jasper that I got on Saturday. I picked it up, along with a bunch of other gemstones from Scratchpatch. This is a place in Seattle that encourages you to come by, and sit in and examine a bunch of gemstones. You can then pick out the ones you like, and pay for them by the bag full. Ravenna and I went there, and we both got a medium bag of assorted rocks, for $8 a piece. It was really fun to take our shoes off and sit on a bunch of pretty tumbled rocks! I liked how they felt on my feet and legs. So next time you’re in Seattle, stop by there and try it out. Science, Art & More is about a block away, so make a day of it!










Jasper is mostly silica and impurities (in this case iron(III) ). It crushed fairly easily with pliers & a sledge hammer, and will probably crush well with a big rock, once I decide to make a production run (not using any modern tools)












I was a little worried that it wouldn’t mix with walnut oil very well, because of how it handled at first. It seemed to repel the oil. But once I started mixing it, it seemed to hold the oil fairly well. Sidenote: It’s amazing how each paint handles so completely differently from each other. I know my pigment particle sizes are really big compared to consumer paints, but it still never ceases to amaze me how different they behave and feel. This pigment is the reddest material that I’ve found so far, although my parent’s burnt soil comes close (not as pure of a red).

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