The Making of the Glencairn Methuselah Window: Page 79

Spatter Modelling Clay Backing ground in ore grinder with turpentine quite a while, thin a little fatty turpentine added and oxidized turpentine stirred 13000 times. Put plenty in – the paint flattens on the slab. I added some of the thinner oxidized turpentine also. I spattered the Backing in patches on the back, but made a more even film on the front.

I went over the back and spattered a very delicate film on the barest parts.