PDF quality when converted

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nate12o6

PDF quality when converted

Post by nate12o6 » 2007-03-21T14:35:32-07:00

Any time i convert a 300 dpi pdf file it says that it is only 72 dpi. When i set density to 300 it puts very small edges on my image and the width is 1 pixel larger than it should be. Any clue what could be wrong?

The command i am useing is:

convert -density 300 BMMXSpicy32oz4C.pdf BMMXSpicy32oz4C.jpg

It does the same wether i keep it a pdf or if i change it to jpg.

Thanks in advance for any help on this!

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magick
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Re: PDF quality when converted

Post by magick » 2007-03-21T15:55:14-07:00

We assure you the density is set in your JPEG image. We follow the JFIF standard that provides for a resolution setting in the image header. However, Adobe ignores the standard and instead looks for an EXIF profile resolution tag. If the EXIF tag does not exist, it assumes 72DPI. Recent versions of ImageMagick updates the EXIF resolution tag if the image has an existing EXIF profile associated with it.

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anthony
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Re: PDF quality when converted

Post by anthony » 2007-03-21T18:30:25-07:00

Which begs the question of adding a Blank EXIF profile (and setting its density/resolution) to a new JPG image.

I supose a EXIF profile could be extracted and edited to only contain minimal set of defaults (say pretending it was an ImageMagick camera). If anyone has a source for such a profile for publication, that would be great.
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nate12o6

Re: PDF quality when converted

Post by nate12o6 » 2007-03-22T06:26:00-07:00

Well eventually the dpi gets to 300 when i use the -density 300. But the problem lies in the quality. I would like this to go into print but there are jagged edges on the image. I am thinking that has to do with it not being the right width and height. The jpg that i convert with photoshop is 1 less pix in length and height but is correct. When i convert or even just open a pdf and write it back out it adds an extra pix to the length and height and you can see that there is a mess up in the image. Do you think that this has something to do with the exif profile in the pdf that says that its dpi is 72? And if so could you point me in the direction on how to fix this? I am new to using profiles. Thanks!

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anthony
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Re: PDF quality when converted

Post by anthony » 2007-03-22T16:53:34-07:00

For quality, use a larger DPI density, then resize using -resample to set the actual density wanted. It is slower but should remove the ragged edge

Code: Select all

  convert -density 1200 page.pdf  -resample 300  page.jpg
Anthony Thyssen -- Webmaster for ImageMagick Example Pages
https://imagemagick.org/Usage/

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