Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site watrose.UUCP
Path: utzoo!watmath!watrose!dmmartindale
From: dmmartindale@watrose.UUCP (Dave Martindale)
Newsgroups: net.graphics
Subject: Re: avoiding glare
Message-ID: <145@watrose.UUCP>
Date: Thu, 22-Dec-83 13:45:21 EST
Article-I.D.: watrose.145
Posted: Thu Dec 22 13:45:21 1983
Date-Received: Fri, 23-Dec-83 06:53:03 EST
References: <4233@rochester.UUCP>
Organization: U of Waterloo, Ontario
Lines: 30

There seem to be two separate problems with light on the screen.
Light which falls directly on the screen washes out the darker areas
of the image, reducing contrast and colour saturation.  Light sources
anywhere within a cone projecting out from the monitor face show
up as bright spots reflecting from the glass CRT face.
If you are doing photography, you have to eliminate both sources of
light.  If you are just viewing an image on the monitor, the reflected
images seem to be easy for people to ignore as long as they are not
too bright.

In the graphics lab at Waterloo, where there may be several people
using our single Ikonas in sequence, the main colour monitor is in
the main lab area which contains most of the terminals, and we keep
this room fairly dark.  Lighting is by incandescent lamps
on dimmers.  Among other things, this means that we tend to avoid
using terminals with long-persistance phosphors because the smearing
they produce is much worse in a dim room (so we use Genies rather than
Ambassadors).
Most of the terminals in the lab face the end of the room with the
monitor; thus anyone can throw up an image and get an idea of what
it looks like, walking up to the monitor if they want to see fine detail.

This arrangement would not work well if you want to photograph off the
monitor, since you'd have to turn off all the room lights, preventing
anyone from using the terminals.  This isn't really a problem for us,
since most images we generate are intended to be displayed with normal
NTSC television field and line rates and sync, and thus can be recorded
on film using our Dunn camera.

	Dave Martindale