Lightroom strips EXIF SubjectArea tags from images

  • 1
  • Problem
  • Updated 3 years ago
  • Not a Problem
Lightroom can read EXIF SubjectArea data and use it to automatically setup previously tagged faces, but when updating file meta-data, it will strip that tag from the EXIF data and only store it in Lightroom's catalog. LR should save face tagging as SubjectArea so that the data stays with the original file (either directly embedded on in an XMP sidecar file) and can easily be used by other catalogs or other applications. At the very least, it should not delete tags that were present.

You can test this as follows:
(1) Create an image (JPEGs are best to demonstrate, but the problem will happen with DNGs too)
(2) Use another application to tag faces and save them to SubjectArea EXIF tags (this can be done with Exiftool, Picasa, etc.)
(3) Add the image to Lightroom
(4) Notice that Lightroom will automatically use the SubjectArea tags to generate face data
(5) Change some meta-data so that Lightroom will update the meta-data on disk
(6) View the raw meta-data of the updated file and notice that the SubjectArea tags are now removed.

Another way of demonstrating the problem:
(1) Tag a face in Lightroom
(2) Make sure the meta-data is saved
(3) Create a new catalog
(4) Import the previously tagged picture
(5) Notice that it does not automatically pull the faces in since the SubjectArea tags are not present.

This was tested in Lightroom 6.3.
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Daniel S

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Posted 3 years ago

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John R. Ellis, Champion

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We need to tease apart the issues:

- Neither Picasa nor LR use the EXIF:SubjectArea field to store named faces. Rather, they both use XMP regions, as recommended by the Metadata Working Group standard. What leads you to think that Picasa uses EXIF:SubjectArea? When I examine a pic tagged by Picasa with Exiftool, I see the XMP regions but no SubjectArea fields.

- LR 6.3 does save tagged faces back to file metadata. The rectangular regions get saved in the XMP region fields, and the face names get stored in both the region fields and the keyword fields. (Make sure you do Metadata > Save Metadata To File to ensure that all metadata gets written from the catalog back to the file.) When I import such a file into another LR catalog, the face regions, the names assigned to the regions, and the associated person keywords all get imported as well.

- When you import a pic face-tagged by Picasa into LR, LR will display the face rectangles and the names assigned to the faces. However, the name doesn't show up in LR's list of person keywords in the Keyword List. This is because Picasa didn't write a keyword for the name into the metadata. Picasa and LR are both following the MWG standard here but using the standard differently, so you can't say either one is "wrong". It would be better, though, if LR automatically supplied such missing keywords when it imports files that are missing them.
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Daniel S

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You are correct. I listed the wrong tag .. it is the XMP Region tags that is used to store the face regions.

I did some more research and I figured it out. Somehow "Include On Export" got unchecked for most of the People keywords, so it was stripping them from the XMP data on disk (but keeping them in the LR Catalog).