Recipes for Black Drawing Ink and for Casting Bronze
Gall-and-vitriol ink written with spit, a coloured wine, and a plaster mould mixed with burnt ox-horn
A page of workshop recipes written in pen. The first prepares a black writing and drawing medium: dust the paper with powdered gall and vitriol as if varnishing it, then write over it with a pen dipped in saliva to get a black as deep as ink. A related note tells how to darken or colour white wine (turning it vermilion by steeping gall and dissolved vitriol). The last recipe is for casting bronze in a plaster mould, mixing one part burnt ox-horn to every two bowls of plaster.
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Black drawing ink from gall, vitriol and spit
To make paper draw black with saliva, dust it with powdered gall (galla) and vitriol like a varnish, then write with a pen dipped in spit and it will come out black as ink. A companion note steeps pulverized gall in white wine for eight days and dissolves vitriol in water, so that the mixture turns the wine vermilion.
Casting bronze in a plaster mould
For casting bronze in plaster (gesso), take for every two bowls of plaster one of burnt ox-horn, mix them together, and cast. The burnt horn tempers the plaster to withstand the molten metal.