Preserving EXIF data and image.info['dpi'] missing

Ryan Neve <[email protected]> Wed, 20 Feb 2013 15:11:01 -0500
Newsgroups	gmane.comp.python.image
Organization	University of North Carolina Institute of Marine Sciences
Message-ID	<[email protected]>
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I'm using PIL with a time lapse camera to add some text and a few 
reference lines to an image. I'm using jpeg, but may switch to ppm 
(converted from raw). I have two problems.

First, it seems as if PIL can read EXIF data but not write it. Is this 
correct? I've seen a lot of posts asking this question, but no recent 
answers. I really need the EXIF data preserved when I save the image.

Second, when saving, the default dpi is 72, not the original dpi. I saw 
someone suggest:

image.save('file.jpeg', dpi = image.info['dpi'])

but my image.info is {'exif':'very long string...'} with no dpi key.

I ended up hard coding my (300,300) dpi, but this seems less than ideal.

Thanks

-- 
*Ryan Neve*
University of North Carolina
Institute of Marine Sciences
3431 Arendell St
Morehead City, NC 28557
(252) 726-6841 x179
(252) 726.2426 Fax


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    I'm using PIL with a time lapse camera to add some text and a few
    reference lines to an image. I'm using jpeg, but may switch to ppm
    (converted from raw). I have two problems. <br>
    <br>
    First, it seems as if PIL can read EXIF data but not write it. Is
    this correct? I've seen a lot of posts asking this question, but no
    recent answers. I really need the EXIF data preserved when I save
    the image.<br>
    <br>
    Second, when saving, the default dpi is 72, not the original dpi. I
    saw someone suggest:<br>
    <br>
    image.save('file.jpeg', dpi = image.info['dpi'])<br>
    <br>
    but my image.info is {'exif':'very long string...'} with no dpi key.<br>
    <br>
    I ended up hard coding my (300,300) dpi, but this seems less than
    ideal.<br>
    <br>
    Thanks<br>
    <br>
    <div class="moz-signature">-- <br>
      <font size="2"><b>Ryan Neve</b></font><br>
      <font size="2">University of North Carolina</font><br>
      <font size="2">Institute of Marine Sciences</font><br>
      <font size="2">3431 Arendell St</font><br>
      <font size="2">Morehead City, NC 28557</font><br>
      <font size="1">(252) 726-6841 x179</font><br>
      <font size="1">(252) 726.2426 Fax</font>
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