Legacy ImageMagick Discussions Archive

I'm trying to convert from pdf to tiff (with Group4 compression) using ImageMagick command line.
However when i do "convert test.pdf -compress Group4 -density 300 test.tiff" I get a very low quality tiff image

The test.pdf do have the right quality!
Is there a reason why I get such low quality?

Try adding a -density before the pdf: I do not know if you need the -density 300 before the test.tiff

You don't need it before writing the tiff. But it does not hurt either.

That worked, thank you I taught I'd -density, but seemingly it worked now
The file size however is now larger than the maximum for this application

victorzimmer wrote:That worked, thank you I taught I'd -density, but seemingly it worked now
The file size however is now larger than the maximum for this application

Make the density smaller.

OR:

You can use supersampling to get higher quality and reduce the image dimensions.

try

convert -density 288 test.pdf -resize 25% -compress Group4 test.tiff

nominal density is 72
density=288=72*4
resize by 1/4=25%

fmw42 wrote:You can use supersampling to get higher quality and reduce the image dimensions.

convert -density 288 test.pdf -resize 25% -compress Group4 test.tiff

NOTE this will result in an incorrect density! -resize ignored density. So after a resize you do need to reset teh density (if that is important to you).

Alternativally resize using density using -resample
convert -density 288 test.pdf -resample 72 -compress Group4 test.tiff

See IM Example, Image resizing, Resample
http://www.imagemagick.org/Usage/resize/#resample
And PS and PDF supersizing
http://www.imagemagick.org/Usage/text/#postscript