tiff > pdf -> files much too big

[squiddie]

Hello

I'm trying to convert a huge amount of tiffs to pdfs.

My Problem: When I do it on Windows with the actual version (6.4.7-8) the resulting pdfs are about same sized or a bit smaller than the tiffs. I was using convert without any options (convert x.tiff x.pdf).

Then I tried to use it on my Linux (Gentoo-2.6.27-r6) and a self compiled imagemagick 6.4.4.6. The resulting pdfs are between 10 and 30 times bigger than the tiffs. I also tried adding -depth 8, same result.

My compile options were:
yes: X bzip2 corefonts djvu jpeg openexr openmp perl png svg tiff truetype xml zlib
no: -doc -fontconfig -fpx -graphviz -gs -hdri -jbig -jpeg2k -lcms -nocxx -q32 -q8 -raw -wmf

Thanks for any ideas

[magick]

Add -compress zip to your command line to compress your PDF image. You can also choose RLE or JPEG and others.

[squiddie]

OK thanks, it's a bit better, but still too big, even if I choose -compress jpeg -quality 1 the files grow from about 50k to 200k and of course the quality at 1 is not so nice.

The source image are mostly drawings of machine parts, so only black lines on white, if this helps to get a solution. And I get this error:

$ convert 3506-06_05.tiff -compress jpeg -quality 1 3506-06.pdf
convert: 3506-06_05.tiff: unknown field with tag 317 (0x13d) encountered. `TIFFReadDirectory'.

[magick]

Post a URL to one or two of your images so we can download them and determine why they are not compressing properly.

[squiddie]

Thanks for the offer. Would be great if you PM me a mail address to send it to, if you don't mind, as I don't have the possibility to upload it somewhere atm. It's a zip of 700k.

I picked a tiff which is originally 42k in size.
- convert on Windows without compress option creates a pdf of 44k
- same convert command on Linux makes a pdf of 1373k
- a convert on Linux with -compress jpeg makes it 1120k and the quality is slightly worse than on Win.

thanks in advance