I’ve been experimenting with creating a shell white from some mussel shells I found along the Conestogo River a couple of years back. With work beginning on some local-colour plant paintings, I again find myself in need a local white pigment …
Shell White could be the answer: It has a long history of use in some cultures; provides a durable inert pigment; and, represents a material found within many diverse places. The single drawback that I’m aware of, is that it only remains opaque when unvarnished … But this won’t be a detriment in my current application.
The creation of shell white is straight forward enough: Collect your shells; then clean them; then crush them. In my case many of the shells I found has been abandoned for many years, and there wasn’t much organic matter left (I did end up having to grind off the outer part of the shell in order to remove this brown outer layer). This done, it crushed up easily and after being ground created a fine pigment.
But, this first batch is not as white as I had hoped—It has a grey hue that looks white enough when I apply it to a painted area, but on a white background it is decidedly off-white. I don’t know if this was caused by my process or is indicative of the material itself … but I think there’s potential here. I’ve ordered a little bit of Kremer’s Gofun Shirayuki pigment to see what a professionally prepared sample is like; and I’ll be trying another batch for myself soon.
I’ve just recently discovered gofun, and with shipping between Japan and Umbria starting at 50 Euros, I didn’t have much hope of getting any. Then I was reading Cennini and discovered there is a medieval Florentine equivalent. It’s called Bianco San Giovanni, and it’s slaked limestone that’s drenched and dried multiple times, turning it from calcium carbonate to calcium hydroxide, and giving it as far as I can see identical properties to gofun. I got 500 g at Zecchi last week, but I know they deliver around the world. (Ironically, the place that sells gofun – Pigment Tokyo – carries a bunch of Zecchi products.)