Congratulations, paulh, and thanks, mattrom. Thanks also to spike, fiery, dorrien, and buddy for the votes.
I've seen only eight of those twelve "in person."
Until the mid-seventies I was able to buy white lead in large cans from any hardware store, and always used it to prime linen that had been sized with rabbitskin glue. After it became illegal to sell in bulk it was prohibitively expensive to prime with flake white. I tend to paint on panels now anyway.