Pact ink

In occultism, pact ink is the specially prepared ink that a contract with the devil must be written in, otherwise the contract is invalid.

Detailed instructions are rare.

The basic recipe is the same as that for Iron gall ink.

A 14th century recipe for "Pact Ink for Devils and Spirits" is:[1][unreliable source?]

Arthur Edward Waite's Book of Black Magic gives a similar recipe, but saying to include either rock alum or gum arabic, and including directions.