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More => Old Versions => Media Center 13 (Development Ended) => Topic started by: Doof on April 10, 2009, 08:38:03 am

Title: Images Date Problem
Post by: Doof on April 10, 2009, 08:38:03 am
The Problem

I was organizing some photos the other night and found a whole bunch of photos with incorrect dates. I checked my camera and, sure enough, the battery had died at one point and the date and time were set wrong.

My Attempted Fix

I checked the date and time on the camera and compared it to the actual date and time. I then set the camera to the correct date and time so that, at least from now on, it will record the correct date and time. I also added "Must prompt for date and time after detecting battery failure" to my list of criteria for a new camera. ;)

I found that MS Pro Photo Tools has a way of fixing the date and time in the EXIF, IPTC, and GPS tags in my photos. So I tested one. I loaded it up into Pro Photo Tools and set the date and time and told it to copy that date and time to all three (EXIF, IPTC, & GPS) tags. And then I saved the image.

In MC, I took a look at the metatag information in the Tag AW for this image. I could see the information that Pro Phototools had written to the tag and I could see the date information there and it looked correct.

I then ran Update Library (from Tags) on that image and took a look at the [Date (filename friendly)] field. It didn't match what was listed in the EXIF or IPTC tags. The date was still the original date and the time was wiped out entirely. Where does MC get the date information from on an image? If I look at this photo in Windows Explorer, it shows Date Taken as the date and time that I set in Pro Photo Tools.

So now I'm stymied. I have to admit I'm kind of clueless about most of this EXIF and IPTC stuff. It would seem to be fairly simple to update this information in my images using the date & time offset that I have and have MC pick up that new information. Anybody know of another way that would work?
Title: Re: Images Date Problem
Post by: Doof on April 10, 2009, 09:02:25 am
So a little more poking around, using Photoshop shows something interesting. I'm finding date & time values in all kinds of places, and they don't all match.

For instance, on this image I just tested this with:

Original Date: 6/6/2007 14:54:52
Date I Set   : 4/10/2009 09:21:52

(this is from the Photoshop -> File Info -> Advanced)

LocationShows
photoshop:DateCreated2007-05-06
tiff:DateTime2009-04-10T09:21:52-04:00
xap:ModifyDate2009-04-10T09:21:52-04:00
xap:CreateDate2009-04-10T09:21:52-04:00
xap:MetadataDate2009-04-10T09:21:52-04:00
exif:DateTimeOriginal2009-04-10T09:21:52-04:00
exif:DateTimeDigitized2007-05-06T14:54:52-04:00
exif:GPSTimeStamp2009:04:10
pdf:CreationDate2009-04-10T09:21:52-04:00
pdf:ModDate2009-04-10T09:21:52-04:00
png:CreationTime2009-04-10T09:21:52-04:00
png:ModificationTime2009-04-10T09:21:52-04:00

So most of those values show the date & time I set. There are only two places where it shows the old date. I'm guessing it's the exif:DateTimeDigitized tag that MC is getting it's data from? Anyway I can overwrite those values automatically with the others?

The other thing I don't understand is what happened to the time data. Of all of the tags I list above, the only two that don't show a time value is the photoshop:DateCreated and exif:GPSTimeStamp tags, but they don't show a time on the original photo either. Every other tag that MC could be getting it's date from (and it seems pretty likely that it's the exif:DateTimeDigitized tag) shows a time. But after editing it with Pro Photo Tools, the time gets lost.
Title: Re: Images Date Problem
Post by: Doof on April 10, 2009, 10:43:04 am
I found a command line utility that was able to modify the exif:DateTimeDigitized field. Seems like all of the rest of the fields are based on that one as all I did was change that one field on that one image and all the rest fell into place automatically.

But there's still a problem. MC still reports the original date, the time is still missing, and now Photoshop reports that the metadata appears to be damaged, even though it can still read all of that data.

Just an FYI, but I'm doing these tests all on copies of the originals, and starting with a fresh copy each time, so I know that whatever problems I'm seeing are a result of just one procedure, and not being compounded by multiple procedures.
Title: Re: Images Date Problem
Post by: Doof on April 10, 2009, 04:57:04 pm
Just an update, not that anybody seems to care, but just in case anybody else runs into this scenario...

I gave Exifer (http://"http://www.friedemann-schmidt.com/software/exifer/") a shot and it seems to have done the trick. It's funny because it's a fairly old, apparently no longer supported, app, but for whatever reason it's able to edit the EXIF data in a way that is acceptable to MC. It also doesn't damage the metadata in whatever way that Photoshop was complaining about with the commandline utility I found.
Title: Re: Images Date Problem
Post by: darichman on April 10, 2009, 07:49:24 pm
Doof... I ran into this a few months ago. I had some photos which I'd taken in a different time zone, imported them into MC without knowing so and realised all the dates were incorrect. I used another program to add a few hours to each of the photos' EXIF tags and reimported into MC, which failed to show the new tag info. Update from tags didn't help.

I had a backup of the files still on the camera which had never been imported into MC, updated the EXIF dates using the other program and then imported those into MC. The dates were fine.

My conclusion was that once MC has read from the EXIF it won't do so again, but will use IPTC instead? I'm not hugely knowledgable on the internal workings of either of these fields - it would be good, however, to force MC to accept changes to EXIF. Or add full EXIF write support ;)

Is this a bug or a missing feature?
Title: Re: Images Date Problem
Post by: marko on April 11, 2009, 12:59:03 am
The fact that we can't update the EXIF date data with MC is a gaping hole in MC's image armoury. I use AcdSee for this, because I have it, and sometimes, xnview.

xnview has this really neat ability to clear individual tag blocks from image metadata which is clever. They are both in MC's "Send to..." list here.

If I update the EXIF date for an image, MC's auto import picks this up as an external change and updates the library accordingly.

-marko.