Doesn't appear to defeat security envelopes either, which have been around for quite some time.

> -----Original Message-----
> From: David Honig [mailto:honig@sprynet.com]
> Sent: Thursday, December 14, 2000 2:06 PM
> To: R. A. Hettinga; cypherpunks@algebra.com; cryptography@c2.net
> Subject: Re: Perry's Paint Fable comes to mind...
>
>
>
> At 03:50 AM 12/14/00 -0800, R. A. Hettinga wrote:
> >> FOR ALL TO SEE
> >> It's a spray which renders sealed envelopes transparent, making the
> >> letters inside as easy to read as postcards. "It leaves an
> odour for 10
> >> to 15 minutes," says the spray's inventor, but, apart from
> that, "no
> >> evidence at all" that it's been used. While the
> manufacturer describes
> >> "See-Through" as a "non-conductive, non-toxic, environmentally safe
> >> liquid", human rights activists believe "it's an ethically
> questionable
> >> product" which could tempt security forces to bend laws.
> >> http://www.newscientist.com/news/news.jsp?id=ns226930
> >
> >[Lighter fluid and similar stuff works just fine. That's been known
> > for over a hundred years... --Perry]
>
> Wouldn't this be detectable if you scrawled on the envelope with
> an ink succeptible to paper chromatography in that solvent?
>
> You can make primitive (before cheap float glass) windows by
> oiling paper...
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