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Posted: Thu Jul 10, 2008 11:09 pm
by Lyle Neff
Correction: I won't be able to use Gimp, or something like it, until my desktop computer at home is upgraded. Seems Gimp needs a lot more memory and/or processor speed than my 6-year-old PC can handle.
So, unfortunately, my active contributions will be of less-than-desirable image quality for the foreseeable future.
But I'll try to make sure to archive all of my "raw" scans for later.
Posted: Thu Jul 10, 2008 11:46 pm
by Peter
Can't you bypass compression in the imaging program by using a pdf tool that does the compression? (in windows) I always let acrobat do the CCITT.
Posted: Fri Jul 11, 2008 12:16 am
by Lyle Neff
Peter wrote:Can't you bypass compression in the imaging program by using a pdf tool that does the compression? (in windows) I always let acrobat do the CCITT.
Well, yes, but I also want to save space on my storage device(s), so I'd need to compress the TIFs after editing at some point if I want to preserve them.
(I use a scanner/photocopier at the library which apparently compresses each TIF. After I edit and re-save in Arcsoft PhotoStudio, the file-size balloons out of control.)
Posted: Fri Jul 11, 2008 12:45 am
by imslp
Some programs have horrible ways of compressing. For example, some will compress monochrome to grayscale JPEG, which might account for the ballooning of size when uncompressed.
Posted: Fri Jul 11, 2008 2:31 am
by Carolus
Since there was a mention of Mac's here, I though it might be worth mentioning the inexpensive program Graphic Converter, which can be very useful for batch processing TIFFs into CCIT level 4 bitmaps, for converting color and grayscale scans to bitmap (and vice versa), plus some fairly decent editing features.
Not as good as Photoshop to be sure, but also about 1/10th the price.
Posted: Sun Jul 13, 2008 11:47 am
by Vivaldi
To Daphnis,
I'm not actually using a flat-bed scanner, I'm using a Canon ImageClass multi-function printer that has a scanner. I suspect that age might be a factor as well, since I bought this 3-4 years ago. I think I'll have to invest in a high quality flat-bed scanner, which can scan 600dpi in a few seconds rather than half a minute (which is the time my scanner needs).
Posted: Tue Jul 22, 2008 9:43 am
by carmar1791
Does someone know the comand line to convert ccitt group 4 using imagemagick?
The default convesion ("convert input.pdf output.tiff") is very bad,useless for loss of quality.
Conversions made by Gimp are bad too (pdf to tiff).Is there a way to set gimp/imagemagick to convert at level ccitt group 4 ?
Thank'you
Carmar
Posted: Wed Jul 23, 2008 4:41 am
by horndude77
For compressing a monochrome tiff this works fine for me:
convert $1 -compress Group4 $1
The problem is extracting the images from the pdf. There is pdfimages which creates a bunch of pbm's. Unfortunately you lose the original image dpi. If you know that you can do something like this (thrown together quickly):
Code: Select all
#!/bin/sh
#Usage $0 [pdf file]-
PREFIX=prefix
pdfimages $1 $PREFIX
for i in $PREFIX*.pbm
do
convert -density 600x600 $i -negate -compress Group4 `echo $i | sed -e 's_pbm$_tiff_'`
done
tiffcp $PREFIX*.tiff out$PREFIX.tiff
tiff2pdf out$PREFIX.tiff -z -o Compressed_$1
rm $PREFIX*
rm out$PREFIX.tiff
I believe feldmahler used to have a similar script.
Posted: Wed Jul 23, 2008 4:43 am
by horndude77
Posted: Wed Jul 23, 2008 9:22 am
by carmar1791
Thank you.It will be hard to understand all now and atonce. (I have just switch to linux).
Thank you again
Ciao
Carmar