I have two tubes . . .
Finally got around to looking through my supply chests and find I have at least two tubes of Grumbacher burnt sienna.
One is Pre Tested, and the other is Academy (student stuff), both are made of calcined natural iron oxide. The Pre Tested tube is the P023 of which you speak.
I can't believe it's that hard to find. I order this stuff from Dixie Art (they have a web site) all the time.
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