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TIFF and LibTiff Mail List Archive

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1994.09.20 03:03 "TIFF CIEL*a*b* Question (with Answer)", by John M Davison
1994.09.20 07:53 "Re: TIFF CIEL*a*b* Question (with Answer)", by Fredrik Lundh
1994.09.22 08:31 "Re: TIFF CIEL*a*b* Question (with Answer)", by Karsten Spang
1994.09.22 10:13 "A note on (group4) compatibility issues", by Fredrik Lundh
1994.09.22 14:48 "RE: TIFF CIEL*a*b* Question (with Answer)", by Craig Jackson
1994.09.22 15:19 "Re: TIFF CIEL*a*b* Question (with Answer)", by Sam Leffler

1994.09.22 14:48 "RE: TIFF CIEL*a*b* Question (with Answer)", by Craig Jackson

But don't ship such files outside your office... When using Compression=3 or 4, I'd stick to SamplesPerPixel=1, PhotometricInterpretation=0, and RowsPerStrip=ImageLength!

WHAT? You can't be serious! What if your ImageLength and ImageWidth is 10000, 20000, or more? For G3 compression you should stick to the "8k" rule for RowsPerStrip. For G4 this may ruin your compression rate; if you have only one or two scan lines in a strip, 2D compression does not make much sense, in this case you should be more lax about the "8k" rule, and use at least (say) 100 scan lines per strip.

If you're merely using G3 or G4 as a handy compression scheme, you can set RowsPerStrip to whatever you want. However, Fredrik Lundh was absolutely right: if you want to achieve interchange, set RowsPerStrip=ImageLength.

Many programs treat the FAX data as FAX data, not just as some portion of a TIFF file. This especially true when translating to and from other file formats. And of course, FAX applications want to see a FAX image, and they know nothing of RowsPerStrip.

Craig Jackson
craigj@epub.ziff.com
Electronic Publishing,
Information Access Company