Data compression in CIE-Lab and color management
Data compression in CIE-Lab and color management
- Subject: Data compression in CIE-Lab and color management
- From: Henk Gianotten <email@hidden>
- Date: Fri, 10 Nov 2000 00:32:36 +0100
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In a message dated 11/8/00 1:39:39 PM, email@hidden writes:
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>Can anyone comment on how image data compression can be used in a color
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>managed
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>workflow?
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At 18:43 8-11-00 email@hidden wrote:
(Snip)
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but using lossy
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compression denotes a willingness to accept non-identical results. It would
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be quirks where color conversion exagerated JPG artifacts that would be the
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biggest concern,....
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Can you imagine a (database) workflow where you scan in higher resolutions
and store in CIE-Lab (without profile). Compression in Lab with no
compression in the L channel and compression in both a and b. Result less
or as much space needed compared to uncompressed files in regular
resolution.
Decompression prior to transformation to CMYK via Lab-CMYK profile (at the
end)
Result: a sharper image, a better result than any compression in CMYK or
profiled RGB and if you create a CMYK with "long-K" and the right Gray
Component Replacement during the CMYK transformation far better details too.
Our eyes are far more sensitive to the changes in both sharpnes and color
if caused by luminance differences. So keep L signals uncompressed.
The ratio between L and the a and b are mostly 1:2
The MPEG compression schemes for video prove that.
I appreciate your comments
Regards, Henk Gianotten
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Henk W.J. Gianotten, Senior Consultant Giarte Media Group
Prins Hendriklaan 58 3761 DW Soest, The Netherlands
Tel: +31 (0)35 601 22 06 email at home: email@hidden
email at Giarte Media: email@hidden (www.giarte.com)
Any views or opinions are solely those of mine and do not
necessarily represent those of the Giarte Media Group.
www.giarte.com ITsurvey.com de-onderneming.com
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