Ghostscript PDF -> TIFF conversion is awful for me, people rave about it, I alone look sullen

Question

My stomach churns when I see this kind of output.

http://www.freeimagehosting.net/uploads/e1097a5a10.jpg

and this was my command as suggested by Best way to convert pdf files to tiff files

gswin32c.exe -q -dNOPAUSE -sDEVICE=tiffg4 -sOutputFile=a.tif a.pdf -c quit

What am I doing wrong?

(commercial products will not be considered)

-r800? That is a DPI of 800x800, surely that can't be correct. — , Dec 09 '10 at 16:29

danio · Accepted Answer · 2008-10-21T11:26:41.807

15

tiffg4 is a black&white output device. You should use tiff24nc or tiff12nc as the output device colour PDFs - see ghostscript output devices. These will be uncompressed but you could put the resulting TIFFs through imagemagick or similar to resave as compressed TIFF.

edited Oct 21 '08 at 11:26

answered Oct 21 '08 at 11:21

danio

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Thanks for the colour information. After including Philho's advice about resolution im finding my tif shooting up to 20+ megs. This is way beyond. Making use of imagemagick would reduce this? – Setori Oct 22 '08 at 01:35
Yes, ImageMagick (and many other image manipulation tools) can convert uncomressed TIFF to compressed TIFF. Are you sure you need TIFF? 24-bit PNG is a pretty good choice for screen capture. – Chris Dolan Oct 22 '08 at 03:45
must be tiff sadly, the whole backend system is setup for tiff, a change and the whole thing comes down kicking and screaming. Also i just found out it must be black and white... interfacing with legacy systems can be a little of a headache... pdf would be the best. – Setori Oct 22 '08 at 08:15

score 11 · Answer 2 · edited Dec 07 '20 at 08:04

11

I have been using ImageMagick for quite a sometime. It's very nice tool with a lot of features.

Install ImageMagick and run following command. This is what I used on Linux, you may have to replace convert with the correct one.

Below command converts PDFs to CCITT Group 3 standard TIFs (Fax standard):

convert -define quantum:polarity=min-is-white \
        -endian MSB \
        -units PixelsPerInch \
        -density 204x196 \
        -monochrome \
        -compress Fax \
        -sample 1728 \
        "input.pdf" "output.tif"

Also you may use GraphicsMagick, it is also similar to ImageMagick, but ImageMagick more concerns with quality than speed.

edited Dec 07 '20 at 08:04

Glorfindel

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answered Dec 13 '10 at 09:31

Amil Waduwawara

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This is by far the best option I have seen in a long time for converting a text based PDF to TIFF while maintaining decent quality and a low file size. Switching the compress option to Group4 reduces the file size even further, and I maybe seeing things, but it looks like the quality actually got even better. – Jim Walker Sep 14 '16 at 19:39

score 2 · Answer 3 · answered Sep 19 '11 at 05:23

2

Like other posts suggested, use a color format (e.g. -sDEVICE=tiff24nc) and specify a higher resolution (e.g. -r600x600):

gswin32c.exe -q -dNOPAUSE -r600 -sDEVICE=tiff24nc -sOutputFile=a.tif a.pdf -c quit

answered Sep 19 '11 at 05:23

Stephen Quan

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Please do not add an answer when other posts already contain that answer. Instead, upvote the existing post which you agree with. – mah Nov 11 '12 at 15:38

score 1 · Answer 4 · answered Oct 21 '08 at 11:58

It is quite nice for a fax! ;-)

danio's answer is probably the best, if you need a color copy.

I notice also, from the linked thread, that you omitted to specify DPI for the output, hence the bad look... If you need pure dithered B&W, you should use a higher resolution.

I also got a good looking image using NConvert

nconvert -page 1 -out tiff -dpi 200 -c 2 -o c.tif FMD.pdf

I mention it for the record, because I think you need a license to redistribute it (it is free for personal use otherwise).

Not going with Nvonvert, it cant read my pdf document I gave it to convert — Setori, Oct 22 '08 at 01:55

Setori · Answer 5 · 2008-10-22T08:16:47.337

Thanks guys this is what I ended up with

     os.popen(' '.join([
                       self._ghostscriptPath + 'gswin32c.exe', 
                       '-q',
                       '-dNOPAUSE',
                       '-dBATCH',
                       '-r800',
                       '-sDEVICE=tiffg4',
                       '-sPAPERSIZE=a4',
                       '-sOutputFile=%s %s' % (tifDest, pdfSource),
                       ]))

Kurt Pfeifle · Answer 6 · 2012-06-18T21:36:28.283

setori's command does not specify the resolution to use for the tiffg4 output. The consequence is: Ghostscript will use its default setting for that output, which is 204x196dpi.

In order to increase the resolution to 600dpi, add a -r600 commandline parameter:

gswin32c.exe ^
   -o output.tiff ^
   -sDEVICE=tiffg4 ^
   -r600 ^
    input.pdf

Also note that TIFFG4 is the standard fax format and as such it uses black+white/grayscale only, but no colors.

@jeff: Have you ever tried the -dDITHERPPI=<lpi> parameter with Ghostscript? (Reasonable values for lpi are N/5 to N/20, where N is the resolution in dpi. So for -r600 use try with -dDITHERPPI=30 to dDITHERPPI=120).

score 0 · Answer 7 · answered May 01 '12 at 19:54

I ran into the same problem with fax pages.

I was using Imagick in php and this command fixed the way it looked.

$Imagick->blackThresholdImage('grey');

I didn't see any threshold option using 'gs' but convert may also work for you.

convert a.pdf -threshold 60% a.tif

Ghostscript PDF -> TIFF conversion is awful for me, people rave about it, I alone look sullen

7 Answers7

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