Lightroom Classic: Metadata XMP

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Question: When one takes a picture (digital camera) and the metadata of the XMP Dates - (except the creation date) are they carried over from the camera metadata on the time the image was taken? I tested a number of images and this appears to be the case, except for the XMP creation date (that changes once one changes the picture taken date). And will the metadataDate & modifydataDate will they change when picture is edited? Thanks
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JJ Mclean

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Posted 1 year ago

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John R. Ellis, Champion

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The rules for how LR handles dates are fairly involved. In general, LR follows the Metadata Working Group's specifications. Unfortunately, the MWG's Web site has been offline for over a year, but you can get a copy here.   

LR reads the date fields from the photo when it imports it and stores those fields in its catalog. When you save metadata to a file or export a photo, the metadata fields will then be set according to the MWG rules.   

Here's a summary of the fields -- note that the various field names often don't correspond to your intuition or assumptions:

Capture Time: EXIF:DateTimeOriginal, IPTC:DateCreated, XMP:DateCreated [sic]. Stores the capture time of photo (when the shutter was pressed).  LR displays this in the Metadata panel's Capture Date/Time fields.

Digitization Time: EXIF:DateTimeDigitized, IPTC:DigitalCreationDate, XMP:CreateDate [sic]. When the image was first digitized. For photos, that is usually the same as the capture date, but for scans will usually be different. LR displays this in the Metadata panel's Date Time Digitized field. Contrary to the MWG standard, if you use LR's Edit Capture Time command, it will not change the Digitization Time fields accordingly.

Modification Time: EXIF:DateTime, XMP:ModifyDate. When the photo file was modified by software obeying the MWG standard.  LR displays this in the Metadata panel's Date Time field.  Note that LR never changes this field (contrary to the MWG standard).

Metadata Modification Time: XMP:MetadataDate. When any metadata in the file was changed.

Finally, nearly every single app (including LR, Photoshop, Windows File Explorer, and Mac Finder) displays the metadata contained within the file inaccurately. The only reliable tool is the free ExifTool.  It has a steep learning curve, but there are simpler GUIs that invoke ExifTool.


(Edited)
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Dan Hartford Photo

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"Finally, nearly every single app (including LR, Photoshop, Windows File Explorer, and Mac Finder) displays the metadata contained within the file inaccurately. The only reliable tool is the free ExifTool.  It has a steep learning curve, but there are simpler GUIs that invoke ExifTool."

John,  Great summary and very enlightening.  Can you elaborate on your last paragraph in regard to how LR displays the data inaccurately?
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JJ Mclean

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Hey Dan: So sorry I wasn't clear - this is Photoshop CS5.1 "file info advance tab" results and I noticed that just like the GPS time stamp (carrying over collected one-time GPS time data), so when looking at the XMP:MetadataDate and the XMP:ModifyDate. These dates are showing January 21, 2014 at 1:52 and 58 seconds and the applications of Creator Tool and Windows Photo Viewer were used... I've tested WINDOWS PHOTO VIEWER and no changes were made to these files (as expected - unless they were actually modified)... Is that correct? (see screenshot)

And Creator Tool would have been the application in adjusting time... is that correct?

Is this true? Oftentimes, the metadata remains with the file even when the file is transmitted, copied and changes to another format? 

Thank You
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John R. Ellis, Champion

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"in regard to how LR displays the data inaccurately"

I'd have to search this forum for a complete list (painful), but off the top of my head:

- LR doesn't always display the capture-time fields correctly, especially for video.

LR truncated the precision of the latitude/longitude coordinates (this may have been fixed recently). 

- LR's display of lens information (culled from multiple fields) can be very confusing, not displaying all the lens information.

- The Metadata panel often truncates the display of fields that have wrapped to multiple lines.

- LR doesn't display all the metadata fields, which can lead to confusion.
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John R. Ellis, Champion

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I should also say that LR is better than most other apps, e.g. Mac Finder or Windows File Explorer. But if I want to know the truth about what's in metadata, ExifTool is the tool to use.
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Dan Hartford Photo

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Thanks John
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JJ Mclean

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This reply was created from a merged topic originally titled EXIF Metadata Photoshop.

Hi: This is Photoshop CS5.1 "file info advance tab" results and I noticed that just like the GPS time stamp (carrying over collected one-time GPS time data), and when I'm looking at the XMP:MetadataDate and the XMP:ModifyDate. These dates are showing January 21, 2014 at 1:52 and 58 seconds and the
applications of Creator Tool and Windows Photo Viewer were used... I've tested WINDOWS PHOTO VIEWER and no changes were made to these files using it viewing photo, as expected - unless they were actually modified... Is that correct? (see screenshot)

And Creator Tool would have been the application in adjusting the XMP:MetadataDate and the XMP:ModifyDate times... is that correct?

Is this true? Oftentimes, the metadata remains with the file even when the file is
transmitted, copied and changes to another format? 
Thank You!
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JJ Mclean

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This reply was created from a merged topic originally titled Lightroom: Save Custom Metadata in XMP (merging).

Question: When one takes a picture (digital camera) and the metadata of the XMP Dates - (except the creation date) are they carried over from the camera metadata on the time the image was taken? I tested a number of images and this appears to be the case, except for the XMP creation date (that changes once one changes the picture taken date). And will the metadataDate & modifydataDate will they change when picture is edited? Thanks

Note: This conversation was created from a reply on: Lightroom: Save Custom Metadata in XMP.
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Your question is a general question about photo metadata, not specific to any one Adobe product. So I've removed the specific product categories from your topic and merged all your posts into one, to avoid confusing the discussion. (Someone reading this post in Bridge will assume it's a question about Bridge in particular.)
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"Oftentimes, the metadata remains with the file even when the file is transmitted, copied and changes to another format? 

Yes, in general, the metadata fields added by the camera and subsequent apps will remain with the photo, even when the photo is converted to another format (e.g. from raw to JPEG). But the apps may change or add fields, including some of the date fields. Which fields are changed or added depends highly on the app and which commands in the app you give.  There are multiple industry standards, and most apps don't strictly conform to these standards.

With respect to dates:

The Capture Time fields (EXIF:DateTimeOriginal, IPTC:DateCreated, XMP:DateCreated) are generally preserved.

The Digitization Time fields (EXIF:DateTimeDigitized, IPTC:DigitalCreationDate, XMP:CreateDate) may are may not be preserved. If they are missing from the photo, an app may or may add it, either copying it from the Capture Time fields or setting it to "now".

The Metadata Modification Time field (XMP:MetadataDate) is supposed to get changed whenever an app modifies the photo's metadata.

The Modification Time fields (EXIF:DateTime, XMP:ModifyDate) are supposed to get changed to "now" whenever an app modifies the photo or its metadata, but many apps don't do that.

"XMP Dates - (except the creation date)"


Note that the term "creation date" is highly ambiguous -- are you referring to the Capture Time or the Digitization Time?  (The industry has made a mess of this, using Date Created and Create Date for fields with much different meanings.) See my previous post for the difference between Capture Time and Digitization Time.
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JJ Mclean

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perfect understood (sorry for the cross posts) and THANK YOU!
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John R. Ellis, Champion

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"the applications of Creator Tool and Windows Photo Viewer were used ... Creator Tool would have been the application in adjusting time"

No. The relevant line from your screenshot is:

xmp:CreatorTool: Microsoft Windows Photo Viewer 6.1.7600.16385

The metadata field is named "XMP:CreatorTool" and it contains the value "Microsoft Windows Photo Viewer 6.1.7600.16385". The XMP standard says that XMP:CreatorTool should be "the first known tool used to create the resource [the XMP fields]". 

So in this case, it's saying that Windows Photo Viewer is the app that initially added all the XMP fields to the photo. That's entirely possible -- most cameras don't add XMP fields (a few do).  But it's also possible that another app, not conforming to the standard, added the fields initially.

"Creator Tool would have been the application in adjusting the XMP:MetadataDate and the XMP:ModifyDate times"

The XMP:CreatorTool field says nothing about which app might have changed the XMP date fields. It could have been Microsoft Windows Photo Viewer or it could have been a subsequent app.

If you really want to understand what the metadata has to say about the history of changes to a file, upload the file to Dropbox or similar and post the sharing link here.  Then we can use ExifTool to examine all the metadata fields, which will give more hints.  (Attaching the photo to your reply could erase most of the metadata fields.)

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JJ Mclean

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excellent thanks I am using ExifTool and others as additional tools to assist in digital forensics... I appreciate you advice... JJ www.dcrime.com