Re: Ridiculously Enormous PDFs and Printing
Re: Ridiculously Enormous PDFs and Printing
- Subject: Re: Ridiculously Enormous PDFs and Printing
- From: mathew <email@hidden>
- Date: Sun, 10 Aug 2003 17:22:42 -0400
On Friday, Aug 8, 2003, at 14:02 US/Eastern, Chris Hanson wrote:
On Friday, August 8, 2003, at 09:14 AM, mathew wrote:
You know, if you're concerned about file size (not to mention
cross-platform and multi-software compatibility) then you really
ought to be using PNG, not TIFF.
TIFF has poor compression, and the multitude of TIFF variants (with
different algorithms and even different byte ordering) means that
there's no guarantee a TIFF file written by program A will be
readable by program B, even if both claim to support TIFF.
In the printing world, TIFF is king. Why? Because TIFF does not have
"poor compression." TIFF is a container format; the data in a TIFF
can be compressed using poor compression, compressed using very good
compression, or no compression.
Well, PNG is also a container, but that's not the point. The point is
that in general, using common software such as Photoshop, and across a
broad range of file types, TIFF's compression is worse than PNG's.
Often in printing full-resolution plate files are generated. These
are one-bit images at 2400 to 3600 dots per inch. Stored in a TIFF
using CCITT/ITU T.6 Group 4 Fax compression these types of plate files
can be compressed *very* well. (Often down to 10-15MB for a full
plate with crop and trap marks etc. Group 4 Fax is a very efficient
two-dimensional run-length encoding scheme.) And there's plenty of
industry-specific software that can deal with these.
That's all very well if you have a very narrow problem domain, or
there's human intelligence available to help you guess an appropriate
algorithm. If you're trying to produce a general purpose rasterizer,
though, it may not be a good idea to present the user with a choice of
six different algorithms, two palette conventions and two endian
conventions and hope for the best...
mathew
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