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Thu, 5 Aug 1993 13:51:42 -0500 |
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I am forwarding the following on behalf of Joey S. Schwartz--his computer and
that of screen-l have had a tiff and aren't presently speaking to each other.
It's a reply to a message I sent him about his screen-l posting on resolution.
--Keith Nightenhelser [log in to unmask]
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From: IN%"[log in to unmask]" 5-AUG-1993 03:20:39.03
Subj: Fwd: Re: resolution
Organization: Inter/Access, Arts Telecommunications & Media Centre, Toronto,
ON, Canada
Content-transfer-encoding: 7BIT
Here are more accurate numbers, but the way that video is compared to film is
not by screen size (because film is usually projected at non-standardized
lengths for one thing) but by resolving power per one square inch, which is
the same for a T.V. image that is one inch or 100 inches. Another
consideration in video is bandwith, for every 1 megahertz of bandwidth equals
80 scan lines (not to be confused with lines of resolution). So a tape
format like VHS, which has a bandwidth of 3.5mhz, has only approximately 240
scanning lines, which decreases the overall resolution of the NTSC signal. SO
here are the "official" numbers from Thomas A. Ohanian's book DIGITAL
NONLINEAR EDITING: New Approaches to Editing Film and Video:
FORMAT LINES OF RESOLUTION
VHS 200
SVHS 272
STANDARD 3/4" 240
Laserdisc 336
Hi8 320 (luminance portion of the
signal)
Betacam 288
Betacam SP 336
2" Quad 336
1" Type C 336
D1 336
D2 336
D3 255
35mm Film 6x resolution of average "broadcast picture"
[2016 for regular film, 5247 has over 4000
lines of resolution according to Kodak]
(from Ohanian, 212)
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