Newsgroups: comp.arch
Path: utzoo!utgpu!watserv1!watcgl!imax!dave
From: dave@imax.com (Dave Martindale)
Subject: Re: Resolution, etc.
Message-ID: <1990Nov23.154220.29296@imax.com>
Organization: Imax Systems Corporation, Oakville Canada
References: <2928@crdos1.crd.ge.COM> <1990Nov19.195042.19240@imax.com> <2937@crdos1.crd.ge.COM>
Distribution: na
Date: Fri, 23 Nov 90 15:42:20 GMT

In article <2937@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.com (bill davidsen) writes:
>
>  I think it's more a definition of "real world images." It sounds like
>you are working with electronic images, rather than things you can
>actually photograph. I'm talking about the realm of optical viewing of
>physical objects, not any of the other image forming technologies.
>
>  These images don't tend to have the wide smooth sweeps of slowly
>changing color which show artifact. Not that you can't find some images
>somewhere which produce this effect, but that typical images do not lose
>information. Obviously you can say there is a world of information with
>a 36 bit scanner, and I'm missing it all with my 24 bit scanner, so all
>I can say is that what I see works with 256 colors.

No, I'm working primarily with digitized film images.  It is true that
the inherent scanner noise, plus film grain noise, make these images
less likely to show banding effects than images generated entirely by
calculation.  But there are still images that show banding when quantized
to 8 bits.

In addition, your eye is much better at detecting moving edges than
stationary ones.  An image that shows almost-undetectable banding when
you examine a single still frame may have very obvious banding when motion
causes the bands to move.

I believe that the real difference between us is that you're saying
that a 24-bit scanner and 8-bit display gives you screen displays that
look fine for "typical" stationary images - that if 80% of the images
you try show no problems, you're happy.  While I'm saying that if I
need a system that works with 100% of the images that might pass through
it, including moving ones, 24 bits definitely isn't enough.

The two statements aren't incompatible.  I just wished to point out that
some of us require our images to look right 100% of the time, not 80%,
so 8 bits or 24 bits is simply not always sufficient.

(I left this in comp.arch; comp.graphics people have already heard this
stuff before).
