Subtle problem with XMP date handling

jcloudm

So, I'm still a little confused by all this, but I think I found a problem with Smugmug XMP date handling. Examining this picture (http://cloudman.smugmug.com/photos/435051402_sdnPW-O.jpg) with exiftool, you can see there are two DateTimeOriginal stamps - one in the standard EXIF headers and one in the XMP headers. From previous threads, I think I see a conclusion that XMP>EXIF (http://www.dgrin.com/showthread.php?t=45346). In the image I indicated, the XMP date is:

DateTimeOriginal = 2008:11:27 14:08:25Z

The standard EXIF date is:

DateTimeOriginal = 2008:11:27 14:08:25

Note the key difference in that the XMP data that it indicates the referenced time is zulu (GMT) time. For reference, the way the tags wound up like this is by using Photoshop Elements 6 to edit the file; PSE6 appears to convert all the times to GMT time.

Windows Vista prioritizes XMP over EXIF, and is then figures out that the XMP data is GMT time and adjusts the time displayed to be the local time. For example, Windows Vista Explorer shows me that picture has a Date Taken of 7:08AM (I am in Mountain time, which is currently GMT -7).

However, when I look at the Photo Info in Smugmug (http://cloudman.smugmug.com/gallery/6730776_7v6vx#435051402_sdnPW) it gives no indication that the date taken is at zulu time. Since there's also a Time Zone embedded in a different tag in the EXIF data, I would have expected that if the XMP data shows that it's zulu time, the date showed by Photo Info would be adjusted to that time zone time.

I'm not sure if I'd call this a bug, but it's definitely not giving the time I'd like it to give when I click on Photo Info. Do you have any thoughts on how to fix this or workaround it?

Interestingly, it doesn't appear that PSE6 always stores the data this way; other photos I have taken with a different camera appear with a DateTimeOriginal that looks like 2004:03:02 19:05:38-07:00. I think that's because my Canon SD700IS writes that to the EXIF.

Time zones in jpeg headers seem to be very complex, so I'd definitely believe it if I'm misunderstanding something. Help would be appreciated. Thanks.

Andy

Hi, we don't use the date in XMP we use the date in EXIF.

jcloudm

Andy wrote:

Hi, we don't use the date in XMP we use the date in EXIF.

Oh well, too bad. I guess I'll go try to figure out why PSE6 is converting the EXIF date to GMT on pictures from my Nikon D60 but not on pictures from my Canon SD700IS. If anyone else out there has any tips, let me know.

jcloudm

jcloudm wrote:

Oh well, too bad. I guess I'll go try to figure out why PSE6 is converting the EXIF date to GMT on pictures from my Nikon D60 but not on pictures from my Canon SD700IS. If anyone else out there has any tips, let me know.

Well, with some more research, I stumbled across psedbtool, which corrects a known bug that Adobe apparently is not interested in fixing.

This tool (http://www.johnrellis.com/psedbtool/#_Writing_File_Metadata) will examine PSE6 or PSE7 catalogs on Windows and make sure that all the EXIF and XMP and IPTC data matches the date that PSE knows about, which is right in my case. I still don't know why sometimes it writes the EXIF to GMT, but it's a known bug listed on that page:

Some of the problems with PSE’s File > Write Keyword Tag and Properties Info command include:
-When writing keyword tags, it never deletes old keywords from the file – it just appends new ones. So if you rename a keyword or remove a keyword from a file, that change won’t get written to the file’s metadata.
-For date/times before 2007, it uses the incorrect rules for US Daylight Savings Time, resulting in times that are off by an hour for a few weeks in the spring and fall.
-When writing EXIF DateTimeOriginal, sometimes it writes the time in UTC rather than in local time, causing other tools to show times that are off by many hours.
-It doesn’t always write IPTC:Caption-Abstract, IPTC:Keywords, or EXIF:Rating, causing older tools that don’t understand the XMP versions of those tags to get the wrong values for captions, keywords, and ratings.
-It often doesn’t update sidecars for Nikon NEF raw files.
-It doesn’t update PDF files.
-It doesn’t write sidecars for formats like BMP that don’t support metadata.
-It doesn’t write GPS/map locations to some formats, including TIFFs produced by Nikon and Epson scanners.

Personally, I guess I'd like to make a feature request that Smugmug start accepting XMP date instead of just EXIF date. If we decided that XMP caption is chosen over EXIF caption back in 2006 (http://www.dgrin.com/showthread.php?t=45346), then why isn't it true for date data as well? Adobe seems to be moving away from strong EXIF support, and PSE is a major force IMO.

My two cents. I hope this helps others who might run into the same problem.