🚀 go-pugleaf

Hi ... I sent this message to comp.graphics.misc a few days ago,
but never received a response.  Given that I'm doing this work on
Linux (1.2.13), and that I saw another graphics question here
recently, I thought I'd send it to aus.computers.linux as well.

I'm currently using the NETPBM toolbox to process a (growing) number
of scanned images.  The beauty of the toolbox approach, I find, versus
using any interactive graphics package, is that I can run a script to
do all the work "automatically", rather than labouriously being forced
to manually point/click for each image.

For example, I am using various parts of the PBM toolkit to resize,
rotate and normalise images, and finally "print" an image to a HP
laserjet output format, all in a very simple shellscript, under Linux.

Unfortuately, I find that the quality of printouts I get for a HP
Laserjet 3 is much less than that I can achieve from at least one
MS Windows interactive package that I use.

In NETPBM I use something like the following pipeline to create a
scaled up output image for a HP Laserjet 3 from a scanned PCX 
input file:

  pcxtoppm FILE | pnmscale -xysize 2330 3350 | ppmtopgm | pgmtopbm |
       pbmtolj -resolution 300 > LASERIMAGE

and when I print the image to a Laserjet 3 the result is most
definitely of lesser quality than the same PCX file printed to a "HP
Laserjet 3" driver in PhotoFinish, an MS Windows program that
I use.  The PBM output has little patterns
in what should be (and is in the PhotoFinish output) an even pattern
of gray.

1.  Is this because NETPBM only understands the original HP laserjet,
     and the windows package works with a Laserjet 3?  Or does
     reducing an image to PBM format elminate some of the gray-scale
     information that PhotoFinish may use?  (I know very little about 
     such things; I don't even know if a Laserjet 3 can handle varying
     shades of gray, or if it's strictly black-and-white)

2.  Could I get better results by putting the 'pnmscale' comand
     at a later stage?  Looking at this I just realised that it would
     certainly speed things up if I put it just before the 'pbmtolj'
     call!

3.  Can anyone advise me of a package - preferably something under
     Unix or DOS that I can "plug into" my scripts - which can produce
     (superior) HP Laserjet 3 (or 4) images from PCX, TIF, PBM or any
     other popular image formats?

Thanks for any help.  I'm fairly inexperienced in the world of
graphics, and would appreciate pointers in learning how this all
works.


Bradley Rosser
brad@pinerivers.qld.gov.au