Where does the XMP-exif:DateTimeDigitized tag come from in ExifTool?

[StarGeek]

I think this is what the question is.

DateTimeDigitized (aka EXIF:CreateDate) is defined in the DC-008-Translation-2019-E.pdf, page 53 (Exchangeable image file format for digital still cameras: Exif Version 2.32).

The DC-010-2017_E.pdf, page 13 (Exif 2.31 metadata for XMP) states that the XMP name for DateTimeDigitized is XMP:CreateDate.

But the XMP-exif:DateTimeDigitized does not seem to be defined in that standard.  The only other place DateTimeDigitized is mentioned in that doc is with regards to SubSecTimeDigitized and OffsetTimeDigitized.  This seems to also apply to some of the other XMP-exif tags. 

So I think the question is, What is the standard that defines the XMP-exif:DateTimeDigitized tag.

[Phil Harvey]

Thanks StarGeek.

I had thought the link from the Exiftool XMP-exif tags documentation was for the EXIF for XMP specification, but that is DC-010, not DC-008.  I should fix this.  It is true that the XMP-exif:DateTimeDigitized tag does not exist in DC-010, but it did exist in earlier versions of the XMP specification.

- Phil

Edit:  No, wait.  The Exiftool XMP-exif tags documentation does reference DC-010 as it should, so ignore my first two sentences.  It seems that the confusion may be just because XMP-exif:DateTimeDigitized does not exist in this specification as I thought it did.  But it does exist in earlier XMP specifications.

[Jom]

I think this is what the question is.

DateTimeDigitized (aka EXIF:CreateDate) is defined in the DC-008-Translation-2019-E.pdf, page 53 (Exchangeable image file format for digital still cameras: Exif Version 2.32).

The DC-010-2017_E.pdf, page 13 (Exif 2.31 metadata for XMP) states that the XMP name for DateTimeDigitized is XMP:CreateDate.

But the XMP-exif:DateTimeDigitized does not seem to be defined in that standard.  The only other place DateTimeDigitized is mentioned in that doc is with regards to SubSecTimeDigitized and OffsetTimeDigitized.  This seems to also apply to some of the other XMP-exif tags. 

So I think the question is, What is the standard that defines the XMP-exif:DateTimeDigitized tag.

YESSS!!!

Thanks StarGeek. Only I didn't look at Exif 2.32, because It hasn't been approved yet (if I translated it correctly). I only watched the Exif 2.31.

[Jom]

It seems that the confusion may be just because XMP-exif:DateTimeDigitized does not exist in this specification as I thought it did.  But it does exist in earlier XMP specifications.[/i]

So this XMP-exif:DateTimeDigitized tag is now deprecated?
It should not be used for new metadata?

[Phil Harvey]

So this XMP-exif:DateTimeDigitized tag is now deprecated?

I don't know.  All I can say is that it doesn't exist in the current specification.

It should not be used for new metadata?

I can't answer this.  It depends on what you want to use it for, and what software you want to use it with.

- Phil

[Phil Harvey]

Hey.  I have discovered that the Exif 2.32 for XMP specification draft is now available (here).  I'll add support for this in the next release.

- Phil

[Jom]

Hey.  I have discovered that the Exif 2.32 for XMP specification draft is now available (here).  I'll add support for this in the next release.

But this is a draft. Probably, don't need to use it. What if something changes?

[Phil Harvey]

Then I'll update ExifTool with the new version.

But it is unlikely that anything significant would change from this draft.

I wish more specifications were available in draft version because I often find errors in the specifications by implementing them, and it would be good to fix these before the specifications are released.

- Phil

[Jom]

So this XMP-exif:DateTimeDigitized tag is now deprecated?

I don't know.  All I can say is that it doesn't exist in the current specification.

It should not be used for new metadata?

I can't answer this.  It depends on what you want to use it for, and what software you want to use it with.

I use only ExifTool and latest specification (strive).
Therefore, I have a question (sorry). Why ExifTool uses XMP-exif:DateTimeDigitized instead XMP-xmp:CreateDate?

f:\>exiftool -time:all= 20130730_152454.CR2
    1 image files updated

f:\>exiftool -datetimedigitized="2020:02:20 15:43:59+03:00" 20130730_152454.CR2
    1 image files updated

f:\>exiftool -s -G0:1 -time:all 20130730_152454.CR2
[File:System]   FileModifyDate                                           : 2020:02:20 15:46:05+03:00
[File:System]   FileAccessDate                                           : 2020:02:20 15:46:05+03:00
[File:System]   FileCreateDate                                           : 2020:02:20 15:43:59+03:00
[XMP:XMP-exif]  DateTimeDigitized (I expected [XMP:XMP-xmp]  CreateDate in accordance with Exif 2.31) : 2020:02:20 15:43:59+03:00

[Phil Harvey]

I have answered this exact same question 4 times already in this thread.  Please try to understand my previous answers.

[StarGeek]

Therefore, I have a question (sorry). Why ExifTool uses XMP-exif:DateTimeDigitized instead XMP-xmp:CreateDate?

Exiftool only does what you tell it too.  It doesn't force you to use any standards.  If you tell it to write to XMP-exif:DateTimeDigitized, then it writes to that tag.  To force it to write to a completely different tag is not logical.

[Jom]

Thanks. This phrase helped me.

If you tell it to write to XMP-exif:DateTimeDigitized, then it writes to that tag.  To force it to write to a completely different tag is not logical.

I think I understood the reason for the misunderstanding.
When I wrote -datetimedigitized (tag name from Exiff 2.31), I meant it -exif:datetimedigitized.
But for ExifTool it meant -xmp:datetimedigitized (tag name from early XMP spec.).

f:\>exiftool -exif:datetimedigitized="2020:02:20 15:43:59+03:00" 20130730_152454.CR2
Warning: Sorry, exif:DateTimeDigitized doesn't exist or isn't writable
Nothing to do.

I have a appeared question, why can't I write -exif:datetimedigitized, if it meets the specification?

Ok, I'm looking here — https://exiftool.org/TagNames/EXIF.html and I see
0x9004   CreateDate   string   ExifIFD   (called DateTimeDigitized by the EXIF spec.)

Therefore, within ExifTool, I need to write
f:\>exiftool -exif:createdate="7777:02:20 15:43:59+03:00" 20130730_152454.CR2
    1 image files updated

Ok, I have a next appeared question why ExifTool use CreateDate instead DateTimeDigitized?

I'm looking here — https://exiftool.org/TagNames/index.html and I see
Note: If you are familiar with common meta-information tag names, you may find that some ExifTool tag names are different than expected. The usual reason for this is to make the tag names more consistent across different types of meta information. To determine a tag name, either consult this documentation or run exiftool -s on a file containing the information in question.

Now I understand everything above.

But I'm not entirely sure that the automatic translation of this phrase is correct:
"The usual reason for this is to make the tag names more consistent across different types of meta information."
I understand the General meaning, but I can't imagine a specific situation, because I didn't design ExifTool.
Is it possible to get an example?

[Phil Harvey]

"The usual reason for this is to make the tag names more consistent across different types of meta information."
I understand the General meaning, but I can't imagine a specific situation, because I didn't design ExifTool.
Is it possible to get an example?

The ExifTool EXIF tag named CreateDate corresponds to the Exiftool XMP tag named CreateDate.  ie) these tags have the same purpose and the same ExifTool tag name in both EXIF and XMP = more consistent across different types of metadata.

[StarGeek]

Another way to think of it, though it may not be the original intention, is that CreateDate correlates better to the FileCreateDate.  Both the file system tag and the EXIF tag basically refer to the time stamp when the file was created.

[Jom]

Thanks all. This topic can be finished.