Lightroom: Crop metadata from Photomechanic seems to change LR settings

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  • Updated 6 years ago
  • (Edited)
I do not know if this issue is located within Lightroom (4.3) or Photo Mechanic 5. Here is what happens:

- RAW files (Nikon D700/D800) are imported into a Lightroom catalog.
- Images are cropped in Photo Mechanic 5
- Metadata is "read from files" in Lightroom
- Tone Curve in Lightroom, which was originally set to "Medium Contrast" for these - RAW files through Defaults, is now re-set to "Linear"

If the RAW files are FIRST cropped in PM and then imported into LR, the Tone Curve stays at "Medium Contrast" as set by the Default.

Mac OS X 10.8.2, Lightroom 4.3, Photo Mechanic 5.0, build 13507
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Thomas Geist

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Posted 6 years ago

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Steve Sprengel, Champion

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I'm just another user like yourself, and don't have PhotoMechanic 5, but since you have both PM5 and LR4, you can probably figure out what is happening, yourself:

The first question, does PM5 adjust cropping data inside the raw files unless there is an XMP file, already, then does it merely change that XMP file, or does it always just create or modify an XMP file? You can determine this by looking at the folder with your photos in it, watching for when XMP files are created and modified as you do things in PM5 and LR4.
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If PM5 only creates or modifies XMP files then you can easily figure out what is happening by using a text editor:

1) Take a new photo with your camera and don't do anything with LR, yet:
2) Adjust the crop with PM.
3) COPY the XMP file it creates to a new file called whatever_xmp_PM.txt.
4) Delete that XMP file PM created but keep the TXT copy.
5) Import the raw file into LR.and write metadata to file then exit LR.
6) COPY that XMP file LR creates to whatever_xmp_LR.txt.
7) Adjust the crop of the photo in PM5.
8) COPY the XMP file PM5 adjusts to whatever_xmp_LR_PM.txt.
9) Start up LR and Read metadata from file.
10) Write metadata to file.
11) Exit LR.
12) Copy the XMP to whatever_xmp_LR_PM_LR.txt.

Now using a text editor, examine the four .txt files that were copied from the XMP file at various stages and see what is different, paying attention to the tags related to Curve or ToneCurve. Keep in mind that the metadata tag names can be different between Process Version 2012 and older Process Versions and if PM5 isn't aware of this difference then the results might change depending on if the Process Version is set to 2012 or 2010 when manipulating in LR4.

My guess from what you've described is that PM5 is modifying more than just the cropping data if there is an existing XMP file from LR (a difference seen in the curve-specification between whatever_xmp_LR.txt and whatever_xmp_LR_PM.txt), but doesn't write curve data if it creates its own XMP file when none exists.
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If for some reason PM5 is actually changing data in the raw files without creating an XMP file when none exists, then there won't be an XMP file from step 2) to save and delete in steps 3) and 4), above, and you'll need to do the process with two photos, one where you initially crop with PM5 (step 2) and one where you skip the initial PM5 cropping, but you can still examine the other three XMP files in each case.
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john beardsworth

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PM5 appears to write updates to individual fields in a raw file's xmp sidecar, or creates a new sidecar file if one doesn't already exist. It's the latter that is probably happening, so reading the metadata into LR will overwrite anything already in LR settings.

So to do your roundtrip from LR you need to save (Cmd S) metadata back to the raw file's sidecat. Then crop in PM5, which updates the xmp file, and finally read back into LR.