Path: utzoo!attcan!uunet!sugar!ficc!peter
From: peter@ficc.uu.net (Peter da Silva)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Subliminal (RFC1097)
Message-ID: <3993@ficc.uu.net>
Date: 27 Apr 89 13:20:35 GMT
References: <3956@ficc.uu.net> <19890425150305.1.7THSON@GLOWWORM.LispM.SLCS.SLB.COM>
Organization: Xenix Support
Lines: 22

In article <19890425150305.1.7THSON@GLOWWORM.LispM.SLCS.SLB.COM>, 7thSon@SLCS.SLB.COM (Chris Garrigues) writes:
> Two techniques which I haven't experimented with are (a) to dither the
> message into the background pattern on my window system.  This would
> make the message difficult to read, but isn't that the idea?

The problem is that the human visual system is cued to movement and to
certain kinds of borders. If you use differential dithering patterns you
may or may not be able to see the message at all, particularly if the
size of the message is on the order of magnitude of your background.

Consider the success of copy-protected checks, that use two areas of the same
luminance but a different sized mesh of dots to print a ghostly 'VOID' on the
check... one that can't be seen but will produce a visible interference
pattern with the screen in a copy machine.

Of course this might actually have a subliminal effect. Maybe the anxiety
you feel at payday is NOT just related to the size of your paycheck?
-- 
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.

Business: uunet.uu.net!ficc!peter, peter@ficc.uu.net, +1 713 274 5180.
Personal: ...!texbell!sugar!peter, peter@sugar.hackercorp.com.