ImageMagick convert pdf to jpeg has poor text quality after upgrading ImageMagick version to 6.7.8
imagemagick, imagemagick-convert, pdf-conversion
Solution
I see the same problem with your sample file. It looks like ImageMagick's delegates for the PDF conversion may have changed with the new install.
If you try `convert -verbose foo.pdf foo.jpeg`, do you see `-sDEVICE=pngalpha` in the command that gets sent to gs? The pnmraw device has been used in the past, and switching back to that seems to fix the problem for me.
In ImageMagick's `delegates.xml` file (which may be in /etc/ImageMagick, but could be somewhere else depending on your setup), look for the `decode="ps:alpha"` delegate line and change `-sDEVICE=pngalpha` in the command to `-sDEVICE=pnmraw`. (You can probably just search for pngalpha in the file.)
Problem
After upgrading `ImageMagick` text quality got degraded when convert pdf to jpeg: Old image New Image Conversion command: `convert foo.pdf foo.jpeg` Old ImageMagick version: ``` [root@home]# convert -version Version: ImageMagick 6.2.8 05/07/12 Q16 file:/usr/share/ImageMagick-6.2.8/doc/index.html Copyright: Copyright (C) 1999-2006 ImageMagick Studio LLC ``` generated files size: ``` -rw-r--r-- 1 root root 139K Apr 2 16:11 foo-0.jpeg -rw-r--r-- 1 root root 130K Apr 2 16:11 foo-1.jpeg -rw-r--r-- 1 root root 334K Mar 24 14:27 foo.pdf ``` After upgrading ImageMagick ``` [root@home]# convert -version Version: ImageMagick 6.7.8-10 2012-08-17 Q16 http://www.imagemagick.org Copyright: Copyright (C) 1999-2012 ImageMagick Studio LLC Features: OpenMP ``` generated files size: ``` -rw-r--r-- 1 root root 60K Apr 2 16:11 foo-0.jpeg -rw-r--r-- 1 root root 55K Apr 2 16:11 foo-1.jpeg -rw-r--r-- 1 root root 334K Mar 24 14:27 foo.pdf ``` I've tried using `antialias` flag: ``` convert -antialias foo.pdf foo.jpeg ``` Which did nothing, I've tried setting an higher `quality`: ``` convert -quality 100 foo.pdf foo.jpeg ``` and super sampling: ``` convert -density 288 -background white -alpha off foo.pdf -resize 25% foo.jpeg ``` both gave bigger files and better results, but ran more time and had lower quality that the old ImageMagick version. any advises? Link to the file