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Re: Handmade Ink

>From:    Janice Mancinelli Sapp <JanSapp@xxxxxxx>

>There are medieval recipes for making ink which use the galls off of oak
>leaves and copper sulfate(?).

This is true, but copper sulfate (also known as blue vitriol) added to
tannic acid dissolved out of oak galls will make an ink which will eat
through paper or vellum.

Ferrous sulfate (also known as copperas or green vitriol) is what should be
added to tannic acid solution, but copper sulfate is sometimes present as a
contaminant in ferrous sulfate.

Some old recipes for making ferrous sulfate called for placing an iron bar
in the solution of ferrous sulfate because copper would plate out on the
iron, making the crystals of ferrous sulfate fairly pure.

The essential chemistry for manufacturing iron gall inks goes back more
than two thousand years, but there is still a fair amount of confusion
about what makes a *good* iron gall ink.

In June, 1997, a conference about iron-gall ink problems was held in
Amsterdam and the proceedings have just been published as, _Iron-gall Ink
ISBN 90-6918-189-4 (I don't know the price).

In the book, a balanced formula for making iron gall ink calls for 3.6
parts of ferrous sulfate to 1 part of tannic acid.

The only problem with that formula is that neither the form of ferrous
sulfate (crystal or powder) nor the strength of tannic acid is specified.

The confusion continues....


Jack C. Thompson
Thompson Conservation Lab
7549 N. Fenwick
Portland, OR  97217

503/735-3942  (voice/fax)


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