On Sun, 28 Jun 2009 13:07:12 +0200
Noel da Costa <[email protected]> wrote:
| Hi,
|
| I have a PDF file, which a user tells me is 300dpi. It is being
| reported as being 72dpi by identify.
| I'm using ImageMagick 6.5.3-10 on CentOS 5.
|
First PDF and Postscript files generally have no specific resolution
UNLESS they contain a raster image.
Second IM is a raster image processor, do PDF and Postscript files are
converted to raster images at a resolution set using -density
If that is unset it uses 72 dpi.
EG;
convert -density 300 file.pdf pages-%d.png
YOU must specify the resolution you want because these files formats
generally do not specify a specific resolution!
Finally, for improved results you often use a higher density, then
resize the image back to the desired density.
convert -density 900 file.pdf -resample 300 pages-%d.png
If this is NOT what you want then ImageMagick is not the tool you are
looking for.
For more info and alturnatives see...
A word about Vector Image formats
http://www.imagemagick.org/Usage/formats/#vector
Or the specific sections of PDF and Postscript.
Anthony Thyssen ( System Programmer ) <[email protected]>
-----------------------------------------------------------------------------
The nice thing about machines, Roger thought, was that they
couldn't be impressed by rank. They took you as you were.
--- Anne McCaffrey, "Damia's Children"
-----------------------------------------------------------------------------
Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
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