Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uwm.edu!lll-winken!arisia!sgi!shinobu!odin!horus!thant
From: thant@horus.sgi.com (Thant Tessman)
Newsgroups: comp.graphics
Subject: Re: photographing screens
Message-ID: <1627@odin.SGI.COM>
Date: 27 Nov 89 17:10:13 GMT
References: <1406@ulmo1.mt.luth.se> <3777@hydra.gatech.EDU> <18678@watdragon.waterloo.edu>
Sender: news@odin.SGI.COM
Reply-To: thant@horus.sgi.com (Thant Tessman)
Organization: Silicon Graphics, Inc.
Lines: 39


Some things I've discovered that help make better off screen pictures:

At least 1/30 exposure time (as someone else mentioned).  Requires using
a tripod.

Minimize reflections off the screen.  (Turn off the lights.  Cover the
windows.)

The farther away from the screen you can get, the less the curvature of the 
screen warps the image, so if you have a zoom lens, use it.

Make sure the monitor's brightness is adjusted correctly.  The way I do it
is to display solid black, turn up the contrast all the way, and turn down
the brightness until I can't see any 'leaks' in the display.  (I saw a
guy who knew more about monitors do it differently, but I can't 
remember what he did.)

Make sure the gamma is adjusted correctly.  On SGI's there is an image at
/usr/people/4Dgifts/iristools/images/gamcal.bw that is a bunch of alternating
stripes of black/white dots and grey areas.  The more correct the gamma,
the harder it is to see the stripes.  Use the 'gamma' command.

Most important:  Display a pattern of either solid 50% grey, or alternating
black and white stripes.  (If the gamma is adjusted correctly, they should
be about the same brightness.)  Use this to find the appropriate apperature
for a good exposure for all the images.  Don't let the camera try to
compensate 
for large fields of black.  This will just overexpose the bright parts.

I haven't messed with color filters, so I don't know if it's worth it trying to
compensate for the temperature of the monitors or the film.

If you're spending someone else's money, there are color printers and cameras 
that do the right thing.

Good shooting.

thant


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