Path: utzoo!mnetor!uunet!unisoft!gethen!farren
From: farren@gethen.UUCP (Michael J. Farren)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Fixing flicker, & future frame rate issues
Message-ID: <884@gethen.UUCP>
Date: 19 Apr 88 20:13:31 GMT
References: <11157@ut-sally.UUCP> <8528@agate.BERKELEY.EDU> <11182@ut-sally.UUCP> <8577@agate.BERKELEY.EDU> <1367@hubcap.UUCP> <3626@cbmvax.UUCP> <8712@agate.BERKELEY.EDU> <3641@cbmvax.UUCP>
Reply-To: farren@gethen.UUCP (Michael J. Farren)
Organization: There's Unix there in Oakland
Lines: 30

In article <3641@cbmvax.UUCP> hedley@cbmvax.UUCP (Hedley Davis) writes:
>I go further to note that 50 Hz. CRT displays typically flicker.
>By typical, I mean in a well lit enviroment such as an office or workplace. 

I had the job, about three years ago, of evaluating a Thompson CSF
computer system for the purpose of deciding whether a port of an existing
software product to the system would be feasible.  This was a French
system, and came complete with a 50Hz PAL monitor.  When I started to
do the evaluation, I noticed extreme flicker, enough to give me a severe
headache.  Normally, I am NOT sensitive to flicker - I run an interlaced
display on a standard Sony KV1311CR with no problems at all.  So, I 
suspected that there might be something else going on.  I turned off
the lights in the office, and presto, NO flicker.  My supposition was,
and is, that the 60Hz strobe of the flourescent lighting was interacting
with the 50Hz screen update on a low-persistance monitor, producing
"beat" variations in the light input to my eyes.  So, I would suspect
that your "typical" display problems are simply due to the use of
flourescent lighting in your workplace.  Go to an entirely incandescent
lighting system, and the flicker will likely be reduced to a quite
acceptable level.

BTW - this is an example of "true" flicker - changes in the light
output of the _entire_ display, rather than the localized changes
that are annoying in an interlaced display.

-- 
Michael J. Farren             | "INVESTIGATE your point of view, don't just 
{ucbvax, uunet, hoptoad}!     | dogmatize it!  Reflect on it and re-evaluate
        unisoft!gethen!farren | it.  You may want to change your mind someday."
gethen!farren@lll-winken.llnl.gov ----- Tom Reingold, from alt.flame