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From: jdow@gryphon.CTS.COM (Joanne Dow)
Newsgroups: comp.sys.amiga
Subject: Re: 1080 monitor weirdness?
Message-ID: <1977@gryphon.CTS.COM>
Date: Tue, 20-Oct-87 05:07:32 EDT
Article-I.D.: gryphon.1977
Posted: Tue Oct 20 05:07:32 1987
Date-Received: Wed, 21-Oct-87 20:36:14 EDT
References: <4200002@hpesoc1.HP.COM>
Reply-To: jdow@gryphon.CTS.COM (Joanne Dow)
Organization: Wizardess Designs
Lines: 36

In article <4200002@hpesoc1.HP.COM> cunniff@hpesoc1.HP.COM (Ross Cunniff) writes:
>While wasting time with my 1000 last night, I noticed an interesting effect:
>if you create a high-contrast pattern of alternating colors, an interference/
>shadowing/ghosting/whatever pattern appears.  Repeat by:
>
>	Go into Deluxe Paint, 640x200 mode.
>	Fill the screen with a pattern like (R = red, B = black)
>
>	RBRBRBRBRBRBRB...
>	RBRBRBRBRBRBRB...
>	RBRBRBRBRBRBRB...
>	RBRBRBRBRBRBRB...
>	RBRBRBRBRBRBRB...
>
>	The screen will now have a pattern of several intersecting
>	curves of bright and dark areas.  At the very center of
>	the screen, the brighter pixel groups will form a
>	hexagonal packing pattern, which "spirals" outward toward
>	the screen edges.
>
>Any ideas on what causes this?  

This is called a moire' pattern. One of the thngs it can be used for in that
precise configuration is a precision alignment of the monitor's sweep
linearity. It is an interference between your paint pattern and the dots
on the screen.


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