Sunday, September 30, 2007

Ultramarine Blue the Hard Way

I’ve been pretty busy with the project this week. First off, I’ve got a spiffy new Project Status Banner at the top of my blog, for easy reference on how far I’ve come. Also, I’m drying out and prepping the green copper rust from last week (hopefully I’ll be able to make it into a pigment for next entry). The blue clay that I’ve refined is taking a VERY long time to dry. I don’t think it’ll make a good grey pigment, but I might as well run the experiment through its paces.

Lastly, I’ve finally gotten around to grinding and mixing the Lapis Lazuli that I picked up at Mountain Gems in Burnaby. The folks at Mountain Gems were very helpful and friendly. I called ahead before I showed up to see if they had any in stock. Not only did they have some, they also emailed me a link on how to prepare it for paint! Talk about great service.

For those not in the know, Lapis Lazuli is a type of rock that used to be made into a pigment for tempra and oils back in the day. When we discovered a way to make the Ultramarine Blue synthetically, its use as a pigment diminished. This is fine, because it’s a beautiful rock for many other purposes (carving, etc). Note to any stone sculptors and jewelers out there: If you’re doing any Lapis sculpture, please contact me so I can take the unusable chips off your hands! This stuff isn’t cheap!

Here’s the samples I bought, with one small piece already crushed. When crushing, it gives off a distinctive odor (which prompted me to put on my painter’s mask). It smells like a hair salon when someone’s getting a perm!

Here’s a sample of the pigment mixed with walnut oil. Note that it is a bit greyer and duller than the stone. That’s most likely due to one of two things: The impurities in the cheaper Chilean stone is diluting the color, or the act of crushing the stone is making it duller. Art Graham mentioned that this can happen to cobalt blue if you create a dispersion incorrectly. (see factory tour notes)

This final shot shows the difference between my first and second batch. The first batch looked really dull to me, and my guess was that my tools were not clean enough (the copper test rusted my palate knife. I thought I got all the rust off, but looks like I was wrong)

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