Re: [Gimp-print-devel] 1440x2880 mode?

[Robert L K. <rl...@al...>]

   Date: Thu, 22 Jun 2000 08:52:41 +0100
   From: Ralph Corderoy <ra...@in...>

   > I'm experimenting with a 1440x2880 mode (that's correct -- not
   > 2880x1440).  The reasoning behind this is that dither artifacts in
   > 6-color printers often look like "holes" behind dark dots, and that
   > oversampling in the Y direction covers them up.  It does seem to look
   > very smooth, perhaps smoother than 1440x1440, although currently I
   > don't have the matrix working correctly with it.
   > 
   > Anyone have any idea what to name it, if I do decide to put it in?

   I've been confused by the naming so far so here's my 2p's worth.

   Distinguish between `physical' and `pseudo' resolutions.  Am I correct
   in thinking that most exactly match a printer resolution and it is used
   for all calculations?  No super-sampling?  I'd call that a physical
   one.  Ones that are over-sampled before being converted back to a
   physical one could be `pseudo' resolutions.  The printer isn't really
   printing at 1440x2880.  Each pseudo resolution should have an
   accompanying physical one.

All resolutions up to 1440x720 use the same resolution for sampling
(dithering) and printing.  The only two resolutions where there is an
issue are 1440x1440 (which is currently called "1440x720 enhanced")
and 1440x2880 (which I don't have a good name for).  I'm getting rid
of 2880x720; it doesn't have any real advantages over anything else,
and we don't have a matrix that can handle it.

   Hmmm.  I guess I'm really saying there are two resolutions involved all
   the time, logical (better than pseudo) and physical.  Sometimes they're
   the same, 1440x720-1440x720, and sometimes not, 1440x2880-???x???.

"Logical" or "virtual" are good words for people who understand what's
going on, but they won't make any sense to someone who just wants to
print and not worry about details.

   Add onto that a method of error diffusion/dithering naming and have we
   a canonical format where all parameters are given?

       logXxlogY-phyXxphyY-diffused

The dithering is completely independent from the choice of
resolution.

-- 
Robert Krawitz <rl...@al...>      http://www.tiac.net/users/rlk/

Tall Clubs International  --  http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail lp...@uu...
Project lead for The Gimp Print --  http://gimp-print.sourceforge.net

"Linux doesn't dictate how I work, I dictate how Linux works."
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