KOSHER INK

There are many recipes for making kosher ink, though all revolve around the same basic set of ingredients. 

OLD RECIPE
3 grammes of gumy-rabik (gum Arabic)
3 grammes of afatsim (gallnuts)
1 gramme of kankantum (vitriol - i.e. iron or copper soleplate)
1 cup soot from wool
a quarter of a litre of water
Crush the gallnuts into a fine powder (basically this is tannic acid)

Mix all the ingredients together
Cook on an open flame until the residue is left
Strain out the larger lumps of gallnut
Leave for 6 months to turn black - Use as ink!

Writing Scrolls

Ink used in writing STaM is called D’yo. Some recipes found in the Talmud call for an ink using the recipe found here, but boiled down to a paste. Then whenever the scribe was ready to write he simply dropped the ink wafer into a small quantity of water containing gall and used the ink in the same fashion we use water colors today. We have a scroll where perhaps this was the method used and on this scroll we have found places where the quantity of tannic acid was so high that over a period of time holes were burned through the parchment.