Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site dciem.UUCP
Path: utzoo!dciem!king
From: king@dciem.UUCP (Stephen King)
Newsgroups: comp.sys.amiga
Subject: Re: Another A2000 Question (LP monitor smear?)
Message-ID: <2506@dciem.UUCP>
Date: Tue, 27-Oct-87 09:27:52 EST
Article-I.D.: dciem.2506
Posted: Tue Oct 27 09:27:52 1987
Date-Received: Thu, 29-Oct-87 02:35:20 EST
References: <177@tahoma.ARPA> <4410012@hpcvcd.HP>
Reply-To: king@dciem.UUCP (Stephen King)
Organization: D.C.I.E.M., Toronto, Canada
Lines: 31
Summary: 

In article <4410012@hpcvcd.HP> charles@hpcvcd.HP (Charles Brown) writes:
>perceive flicker the same.  I see outrageous flicker where some people
>see none.  I see ficker on televisions with ordinary shows, and on
>movie theatre screens.  I see some flicker on my Sony monitor using my
>A1000 without interlace.  All of this is quite uncomfortable.
>	Charles (its in the eyes) Brown

Agreed. The correct term is Persistence Of Vision. My supervisor is a 
perceptual psychologist and could give you a detailed account of the
phenomenon, but he's not here right now. I also see flicker on my Sony/
Amiga in non-interlaced mode, but only when I'm not looking directly at
the screen. The most sensitive part of the eye is the fovea, a small patch
at the center of the retina. This area is most sensitive to color, and
exhibits the highest persistence. Images cast outside of the fovea are
much more susceptible to flicker. Reducing the screen brightness will also
reduce the apparent flicker. Reduce the room brightness to taste. Don't
laugh, I have visited many graphics houses where the presentation rooms
were quite dark, except for the display screen, and this was with 60Hz
non-interlaced LP monitors, because they tend to wash out in bright light.
I have tried the Amiga in interlaced mode on Conrac and Mitsubishi LP
monitors, but found the colors rather weak and the contrast low, although
there was no noticeable smear in fast moving scenes. Again, the smear depends
on the color of the background. On a black background, smear is sometimes
visible as a faint green after-image, but I did not find it objectionable.
I can provide references if anyone wishes more info.		...sjk


-- 
 * Defence & Civil Institute *		...!utzoo!dciem!king 
 * of Environmental Medicine *		Stephen J King
- Simulation & Training Group -		(416) 635-2149