From: baumbach@atmel.com (Peter Baumbach)
Date: Mon, 2 Aug 93 11:01:28 PDT
To: cypherpunks@toad.com
Subject: Re: money tracing
Message-ID: <9308021742.AA07002@bass.chp.atmel.com>
MIME-Version: 1.0
Content-Type: text/plain


Thug writes:
> The black ink that is used to print the front side of U.S. cash contains a
> very finely ground black iron oxide powder.  The ink is magnetic.  This
> magnetism is used mostly by vending & change machines to distinguish real
> bills from forgeries/photocopies.
>[...]
>           3. Magnetic ink detection.  Real bills are printed with magnetic
>              ink, forgeries/photocopies are not.

Magnetic toner for laser printers does exist.  Its purpose is to allow people
to print their own checks.

Peter Baumbach
baumbach@atmel.com