DNG Converter preview ignores image orientation

  • 2
  • Problem
  • Updated 4 months ago
  • (Edited)
The preview embedded by Adobe DNG Converter does not reflect the Image Orientation flag from the XMP metadata. Mirrored or rotated images always show the original orientation in the preview.
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Gunther Wegner

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Posted 10 months ago

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Thomas Knoll, Employee

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Sorry this is as designed in DNG format, not a bug.    It is the responsibility of any software that uses the embedded previews in DNG format to apply the orientation.

If Adobe changed this, then all the software that correctly applies the orientation would then break.

The reason for this design is I did not want to have re-render the embedded previews every time any software changes the orientation metadata.  That would make rotating DNG files in Bridge or Lightroom very slow.

Please report this bug against any software that is not applying the orientation correctly to embedded previews in DNG format.
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Andrew Rodney

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Last question: the embedded JPEG is in sRGB right no matter how one sets the camera? It's extracted untagged which kind of makes a lot of sense.
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Thomas Knoll, Employee

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Any software that cares about what color space the previews are in should read the DNG tag that specifies the color space the previews are in.  (See the tag "PreviewColorSpace" in the DNG spec).
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Andrew Rodney

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But the JPEGs previews created by Adobe in the conversion to DNG are sRGB? 
Again, thanks for your time. 
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Thomas Knoll, Employee

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With current Adobe code, previews created by the Adobe DNG Converter are either sRGB or Gray Gamma 2.2.  But any utility that you write should NOT assume that will remain so forever in future versions of Adobe code.  Non-Adobe software very well might already be using different preview color spaces.  Any code that cares what color space the previews are in should parse and use the PreviewColorSpace tag, like I said in my previous message.
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Andrew Rodney

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Got it, super clear. Thanks again Thomas.