Problem with "Modify EXIF Date and Time"

KonradTP · October 23, 2017, 06:52:17 PM

Please note my EDIT at the end of this post!

This is my IMATCH version

I'm running a German Windows 10 laptop with latest updates.

My problem:

I have taken a few hundred photos when the time of my camera was off by one hour.
So, I tried to add this one hour using the Tools/Modify EXIF Date and Time
Start of my test with just one test photo:

Next step:

Result:

I see a modification of EXIF Create Date (marked green), but the other fields are unchanged (red).

The pictures were taken by my Canon 5D Mark III and I have done no editing of the picture or change of the metadata beyond this test.

What is wrong?
I have tried to search the forum, but the topics I found confirm my assumption that this should work in theory.

The test worked with photos from other cameras.

EDIT: I was wrong with my remark above that I had done not edited the test picture. Obviously, I had changed the luminance using Adobe Photoshop CS3.
Yes, this a pretty old version, but I had no problems, so far.
When I copied the file from my camera card again, I had no problem modifying the time.
So, the question boils down to: What strange things happen to the metadata using this Photoshop version?

Mario · October 23, 2017, 07:05:18 PM

1. Check the date and time in your file via the ExifTool Command Processor (use the "List File Dates and Times" preset). What does it show?

2. When IMatch re-imports the file, it will set the XMP date and time from the EXIF date and time.

Problem is, always, EXIF has no time zone information. This is always a nuisance and one of the many reasons why EXIF should have been abandoned in favor of XMP 10 years ago. But the camera vendors are cheap and keep their 20 year old EXIF write code running even in the newest camera models.

ExifTool and IMatch use the local time zone when mapping between EXIF and XMP, unless you have configured a dedicated time zone in Edit > Preferences > Metadata 2 (read the help to make sure you understand what this setting means). I have written a lot about this in the help.

KonradTP · October 23, 2017, 10:45:52 PM

Quote from: Mario on October 23, 2017, 07:05:18 PM
1. Check the date and time in your file via the ExifTool Command Processor (use the "List File Dates and Times" preset). What does it show?
...

I used a different test photo:

Original (Camera: Canon EOS 60D)

[File:System] FileModifyDate : 2017:08:20 21:14:39+02:00
[File:System] FileAccessDate : 2017:09:15 00:48:24+02:00
[File:System] FileCreateDate : 2017:07:02 18:34:24+02:00
[EXIF:IFD0] ModifyDate : 2017:07:02 13:46:59
[EXIF:ExifIFD] DateTimeOriginal : 2017:06:24 20:46:37
[EXIF:ExifIFD] CreateDate : 2017:06:24 20:46:37
[EXIF:ExifIFD] SubSecTime : 09
[EXIF:ExifIFD] SubSecTimeOriginal : 09
[EXIF:ExifIFD] SubSecTimeDigitized : 09
[Composite] SubSecCreateDate : 2017:06:24 20:46:37.09
[Composite] SubSecDateTimeOriginal : 2017:06:24 20:46:37.09
[Composite] SubSecModifyDate : 2017:07:02 13:46:59.09

After modification and write by Photoshop CS3

[File:System] FileModifyDate : 2017:10:23 22:49:28+02:00
[File:System] FileAccessDate : 2017:10:23 22:49:28+02:00
[File:System] FileCreateDate : 2017:10:23 22:49:28+02:00
[EXIF:IFD0] ModifyDate : 2017:10:23 22:49:22
[EXIF:ExifIFD] DateTimeOriginal : 2017:06:24 20:46:37
[EXIF:ExifIFD] CreateDate : 2017:06:24 20:46:37
[EXIF:ExifIFD] SubSecTime : 09
[EXIF:ExifIFD] SubSecTimeOriginal : 09
[EXIF:ExifIFD] SubSecTimeDigitized : 09
[XMP:XMP-xmp] ModifyDate : 2017:10:23 22:49:22+02:00
[XMP:XMP-xmp] CreateDate : 2017:06:24 20:46:37+02:00
[XMP:XMP-xmp] MetadataDate : 2017:10:23 22:49:22+02:00
[XMP:XMP-exif] DateTimeOriginal : 2017:06:24 20:46:37+02:00
[XMP:XMP-exif] DateTimeDigitized : 2017:06:24 20:46:37+02:00
[ICC_Profile:ICC-header] ProfileDateTime : 1998:02:09 06:49:00
[Composite] SubSecCreateDate : 2017:06:24 20:46:37.09
[Composite] SubSecDateTimeOriginal : 2017:06:24 20:46:37.09
[Composite] SubSecModifyDate : 2017:10:23 22:49:22.09

and Modify time +1 hour and Rescan now:

[File:System] FileModifyDate : 2017:10:23 22:52:42+02:00
[File:System] FileAccessDate : 2017:10:23 22:49:28+02:00
[File:System] FileCreateDate : 2017:10:23 22:49:28+02:00
[EXIF:IFD0] ModifyDate : 2017:10:23 22:52:41
[EXIF:ExifIFD] DateTimeOriginal : 2017:06:24 20:46:37
[EXIF:ExifIFD] CreateDate : 2017:06:24 21:46:37
[EXIF:ExifIFD] OffsetTime : +02:00
[EXIF:ExifIFD] OffsetTimeDigitized : +02:00
[EXIF:ExifIFD] SubSecTimeOriginal : 09
[IPTC] DigitalCreationDate : 2017:06:24
[IPTC] DigitalCreationTime : 21:46:37+02:00
[XMP:XMP-exif] DateTimeDigitized : 2017:06:24 20:46:37+02:00
[XMP:XMP-exif] DateTimeOriginal : 2017:06:24 20:46:37+02:00
[XMP:XMP-xmp] CreateDate : 2017:06:24 21:46:37+02:00
[XMP:XMP-xmp] MetadataDate : 2017:10:23 22:52:41+02:00
[XMP:XMP-xmp] ModifyDate : 2017:10:23 22:52:41+02:00
[ICC_Profile:ICC-header] ProfileDateTime : 1998:02:09 06:49:00
[Composite] DigitalCreationDateTime : 2017:06:24 21:46:37+02:00
[Composite] SubSecCreateDate : 2017:06:24 21:46:37+02:00
[Composite] SubSecDateTimeOriginal : 2017:06:24 20:46:37.09
[Composite] SubSecModifyDate : 2017:10:23 22:52:41+02:00

Note: My original problem with the mentioned set of photos is solved, but I'm still interested what was really behind it.

EDIT:

Quote from: Mario on October 23, 2017, 07:05:18 PM
...
Problem is, always, EXIF has no time zone information. This is always a nuisance and one of the many reasons why EXIF should have been abandoned in favor of XMP 10 years ago. But the camera vendors are cheap and keep their 20 year old EXIF write code running even in the newest camera models.

ExifTool and IMatch use the local time zone when mapping between EXIF and XMP, unless you have configured a dedicated time zone in Edit > Preferences > Metadata 2 (read the help to make sure you understand what this setting means). I have written a lot about this in the help.

I have no special time zone setting in Metadata 2.
Actually, looking at the output of the ExifTool Command Processor I do not see why the "Modify time" cannot update the fields correctly after the Photoshop changes.

EDIT2:
Here the time/date listings for the original & Modify time + 1 hour (without any Photoshop interference):

[File:System] FileModifyDate : 2017:10:23 23:09:46+02:00
[File:System] FileAccessDate : 2017:09:15 00:48:24+02:00
[File:System] FileCreateDate : 2017:07:02 18:34:24+02:00
[EXIF:IFD0] ModifyDate : 2017:10:23 23:09:45
[EXIF:ExifIFD] DateTimeOriginal : 2017:06:24 21:46:37
[EXIF:ExifIFD] CreateDate : 2017:06:24 21:46:37
[EXIF:ExifIFD] OffsetTime : +02:00
[EXIF:ExifIFD] SubSecTimeOriginal : 09
[EXIF:ExifIFD] SubSecTimeDigitized : 09
[XMP:XMP-xmp] MetadataDate : 2017:10:23 23:09:45+02:00
[XMP:XMP-xmp] ModifyDate : 2017:10:23 23:09:45+02:00
[Composite] SubSecCreateDate : 2017:06:24 21:46:37.09
[Composite] SubSecDateTimeOriginal : 2017:06:24 21:46:37.09
[Composite] SubSecModifyDate : 2017:10:23 23:09:45+02:00

Mario · October 24, 2017, 07:41:52 AM

I'm not sure that I can follow. Is the problem solved, or not?

If the problem is not solved, open the ExifTool output panel (View > Panels > Output...) and then use the "Modify EXIF..." command on one of your files.
Then copy/paste the contents of the output panel in your reply. This will show us what ExifTool is writing to the file.

I have never heard that this command would produce differing time stamps. Unless the time stamps (created/digitized) in the file were different to begin with - in that case both would be shifted by the same amount, producing different time stamps again. And after the re-import the XMP time stamps shown in IMatch should match EXIF date and time in the file. I have just tried, and it works perfectly.

Shifting by + one hour produces these ExifTool commands:

-XMP-photoshop:DateCreated+=0000:00:00 01:00:00
-XMP-xmp:CreateDate+=0000:00:00 01:00:00
-XMP:MetadataDate=now
-XMP:ModifyDate=now

which shift both timestamps by +1 hour, then updating the XMP metadata and modify date to the current date and time. This is fully correct.

KonradTP · October 24, 2017, 03:06:45 PM

My posts are reflecting my own learning process, so, I might have been not clear enough. Sorry

My problem is solved in the sense that I can work around it.
I have just used the "Modify EXIF Date and Time" on the original camera files. I had not done much editing using Photoshop on the set of files in question.
So, the effort was not so high to repeat this editing afterwards.

Still, I do not understand why the "Modify EXIF Date and Time" does not work as expected after I have rewritten a file with my Photoshop CS3 version 10.0 bought in 2008 (please, look at #4 in my example below).

Let me make a new start with a new example (similar to the example in my second post):

Here are four links to copies of a photo taken with my Canon 5D Mark III

#1 original file copied from the camera

#2= copy of #1; afterwards: Modify EXIF Date and Time +1 hour

#3= copy of #1; afterwards changed and rewritten by Adobe Photoshop CS3

#4= copy of #3; afterwards: Modify EXIF Date and Time +1 hour

Here follow the results of ExifTool Command Processor/List File Date and Times -time:all -a -G0:1 -s {Files}
(everything is as I had expected less #4; I cannot understand why the "Modify EXIF Date and Time" should not work after the change/rewrite by Photoshop CS3):

#1
[File:System] FileModifyDate : 2017:03:29 12:49:37+02:00
[File:System] FileAccessDate : 2017:10:24 13:30:44+02:00
[File:System] FileCreateDate : 2017:10:24 13:30:44+02:00
[EXIF:IFD0] ModifyDate : 2017:03:29 12:49:35
[EXIF:ExifIFD] DateTimeOriginal : 2017:03:29 12:49:35
[EXIF:ExifIFD] CreateDate : 2017:03:29 12:49:35
[MakerNotes:Canon] TimeZone : +02:00
[MakerNotes:Canon] TimeZoneCity : Paris
[MakerNotes:Canon] DaylightSavings : On
[EXIF:ExifIFD] SubSecTime : 59
[EXIF:ExifIFD] SubSecTimeOriginal : 59
[EXIF:ExifIFD] SubSecTimeDigitized : 59
[Composite] SubSecCreateDate : 2017:03:29 12:49:35.59
[Composite] SubSecDateTimeOriginal : 2017:03:29 12:49:35.59
[Composite] SubSecModifyDate : 2017:03:29 12:49:35.59

#2

[File:System] FileModifyDate : 2017:10:24 14:06:43+02:00
[File:System] FileAccessDate : 2017:10:24 13:30:44+02:00
[File:System] FileCreateDate : 2017:10:24 13:30:44+02:00
[EXIF:IFD0] ModifyDate : 2017:10:24 14:06:40
[EXIF:ExifIFD] DateTimeOriginal : 2017:03:29 13:49:35
[EXIF:ExifIFD] CreateDate : 2017:03:29 13:49:35
[EXIF:ExifIFD] OffsetTime : +02:00
[MakerNotes:Canon] TimeZone : +02:00
[MakerNotes:Canon] TimeZoneCity : Paris
[MakerNotes:Canon] DaylightSavings : On
[EXIF:ExifIFD] SubSecTimeOriginal : 59
[EXIF:ExifIFD] SubSecTimeDigitized : 59
[XMP:XMP-xmp] MetadataDate : 2017:10:24 14:06:40+02:00
[XMP:XMP-xmp] ModifyDate : 2017:10:24 14:06:40+02:00
[Composite] SubSecCreateDate : 2017:03:29 13:49:35.59
[Composite] SubSecDateTimeOriginal : 2017:03:29 13:49:35.59
[Composite] SubSecModifyDate : 2017:10:24 14:06:40+02:00

#3

[File:System] FileModifyDate : 2017:10:24 14:07:52+02:00
[File:System] FileAccessDate : 2017:10:24 14:07:51+02:00
[File:System] FileCreateDate : 2017:10:24 14:07:51+02:00
[EXIF:IFD0] ModifyDate : 2017:10:24 14:07:45
[EXIF:ExifIFD] DateTimeOriginal : 2017:03:29 12:49:35
[EXIF:ExifIFD] CreateDate : 2017:03:29 12:49:35
[EXIF:ExifIFD] SubSecTime : 59
[EXIF:ExifIFD] SubSecTimeOriginal : 59
[EXIF:ExifIFD] SubSecTimeDigitized : 59
[XMP:XMP-xmp] ModifyDate : 2017:10:24 14:07:45+02:00
[XMP:XMP-xmp] CreateDate : 2017:03:29 12:49:35+02:00
[XMP:XMP-xmp] MetadataDate : 2017:10:24 14:07:45+02:00
[XMP:XMP-exif] DateTimeOriginal : 2017:03:29 12:49:35+02:00
[XMP:XMP-exif] DateTimeDigitized : 2017:03:29 12:49:35+02:00
[ICC_Profile:ICC-header] ProfileDateTime : 1998:02:09 06:49:00
[Composite] SubSecCreateDate : 2017:03:29 12:49:35.59
[Composite] SubSecDateTimeOriginal : 2017:03:29 12:49:35.59
[Composite] SubSecModifyDate : 2017:10:24 14:07:45.59

#4

[File:System] FileModifyDate : 2017:10:24 14:11:29+02:00
[File:System] FileAccessDate : 2017:10:24 14:07:51+02:00
[File:System] FileCreateDate : 2017:10:24 14:07:51+02:00
[EXIF:IFD0] ModifyDate : 2017:10:24 14:11:28
[EXIF:ExifIFD] DateTimeOriginal : 2017:03:29 12:49:35
[EXIF:ExifIFD] CreateDate : 2017:03:29 13:49:35
[EXIF:ExifIFD] OffsetTime : +02:00
[EXIF:ExifIFD] OffsetTimeDigitized : +02:00
[EXIF:ExifIFD] SubSecTimeOriginal : 59
[IPTC] DigitalCreationDate : 2017:03:29
[IPTC] DigitalCreationTime : 13:49:35+02:00
[XMP:XMP-exif] DateTimeDigitized : 2017:03:29 12:49:35+02:00
[XMP:XMP-exif] DateTimeOriginal : 2017:03:29 12:49:35+02:00
[XMP:XMP-xmp] CreateDate : 2017:03:29 13:49:35+02:00
[XMP:XMP-xmp] MetadataDate : 2017:10:24 14:11:28+02:00
[XMP:XMP-xmp] ModifyDate : 2017:10:24 14:11:28+02:00
[ICC_Profile:ICC-header] ProfileDateTime : 1998:02:09 06:49:00
[Composite] DigitalCreationDateTime : 2017:03:29 13:49:35+02:00
[Composite] SubSecCreateDate : 2017:03:29 13:49:35+02:00
[Composite] SubSecDateTimeOriginal : 2017:03:29 12:49:35.59
[Composite] SubSecModifyDate : 2017:10:24 14:11:28+02:00

Mario · October 24, 2017, 03:15:52 PM

What do you mean by "change/rewrite Photoshop CS3"?
CS3 is way old and uses a quite buggy XMP processor. It may well be that it messes up metadata.

Is the time in the file correct after you have used the Modify EXIF date/time in IMatch?
If this is the case, the problem is PS.

KonradTP · October 24, 2017, 05:17:10 PM

^
I mean that the file #3 was changed using CS3 and written back after this change.
(I know that CS3 is old, but a newer version is pretty expensive.)

I do not see suspicious date/time values looking at the list date/time under #3 above. Do you?
You could download my file #3 and try it yourself.

CS3 can certainly mess up the metadata, but the output under #3 does not prove this theory.

Anyway, as I have found a workaround, I do not want to cause further effort.
I can live with the workaround.

Quote from: Mario on October 24, 2017, 03:15:52 PM
....
Is the time in the file correct after you have used the Modify EXIF date/time in IMatch?
If this is the case, the problem is PS.

Please, have a look at the time fields in my post above.
The IMATCH Modify Date and Time tool works for #2.
After I have edited a copy of the file (see #3), I have tried the command on this file and performed the Modify + 1 hour.
Result under #4 shows differing times.

Mario · October 24, 2017, 06:09:44 PM

It's still not clear what #1 to #2 means, sorry.

#1 is probably the file before you used the Modify Exif... tool in IMatch?
#2 are the contents of the file after?

But what do #3 and #4 mean? Where does PC come into play?

I assume that the date and time was correct after you modified them in IMatch.
Then you did what with the file in CS3? And then you did what with the file in IMatch afterwards?

#3

[XMP:XMP-exif] DateTimeOriginal : 2017:03:29 12:49:35+02:00
[XMP:XMP-exif] DateTimeDigitized : 2017:03:29 12:49:35+02:00

#4

[XMP:XMP-exif] DateTimeDigitized : 2017:03:29 12:49:35+02:00
[XMP:XMP-exif] DateTimeOriginal : 2017:03:29 12:49:35+02:00

You colored this red, but it is the same timestamp in #3 and 4.
Only CreateDate has changed,

After you updated the file in IMatch, CreateDate is 2017:03:29 13:49:35

Photoshop sets this to 2017:03:29 12:49:35 (#3) ?

and in #4 it is again 2017:03:29 13:49:35+02:00.
So it seems to me that ExifTool has corrected whatever PS has done.

From the Metadata Working Group guides:

Digitized Date/Time – Creation date of the digital representation

Exif DateTimeDigitized (36868, 0x9004) and SubSecTimeDigitized (37522, 0x9292)
IPTC DigitalCreationDate (IIM 2:62, 0x023E) and DigitalCreationTime (IIM 2:63, 0x023F)

mapped to

XMP (xmp:CreateDate)

Your sample file shows:

[EXIF:ExifIFD] DateTimeOriginal : 2017:03:29 12:49:35
[EXIF:ExifIFD] CreateDate : 2017:03:29 12:49:35

and after I have shifted the time by +1 hour in IMatch, it shows:

[EXIF:ExifIFD] DateTimeOriginal : 2017:03:29 13:49:35
[EXIF:ExifIFD] CreateDate : 2017:03:29 13:49:35

which is correct.

KonradTP · October 24, 2017, 06:38:57 PM

I had written:

Here are four links to copies of a photo taken with my Canon 5D Mark III

#1 original file copied from the camera

#2= copy of #1; afterwards: Modify EXIF Date and Time +1 hour

#3= copy of #1; afterwards changed and rewritten by Adobe Photoshop CS3

#4= copy of #3; afterwards: Modify EXIF Date and Time +1 hour

I'm not sure if I can describe this much clearer.

I provided links to four files and #1,#2,#3.#4 are symbolic names for these.
You can download all four if you want and look at the time fields.
I have provided the output of the "list date time" for all four files in the post above under the tags #1,#2,#3,#4 in the lower part of the post.
#3 is the file after editing the original (#1) with Photoshop.
#4 is the file after "Modify time +1 hour" to file #3.
Here you see inconsistent times.

What do you mean by "PC"?

More important:
I have made an experiment using Gimp 2.8 and got the same problem:
After editing the file with Gimp 2.8 the "Modify time +1 hour" creates the same inconsistent times shown under the tag #4 above:
Have a look at the red/green colours: Green as expected; Red still one hour off.

Here is the output of the "list date/time" for this GIMP edited file (I have marked the time fields with green/red again):

[File:System] FileModifyDate : 2017:10:24 18:12:07+02:00
[File:System] FileAccessDate : 2017:10:24 18:11:00+02:00
[File:System] FileCreateDate : 2017:10:24 18:11:00+02:00
[EXIF:IFD0] ModifyDate : 2017:10:24 18:12:06
[EXIF:ExifIFD] DateTimeOriginal : 2017:03:29 12:49:35
[EXIF:ExifIFD] CreateDate : 2017:03:29 13:49:35
[EXIF:ExifIFD] OffsetTime : +02:00
[MakerNotes:Canon] TimeZone : +02:00
[MakerNotes:Canon] TimeZoneCity : Paris
[MakerNotes:Canon] DaylightSavings : On
[EXIF:ExifIFD] SubSecTimeOriginal : 59
[EXIF:ExifIFD] SubSecTimeDigitized : 59
[XMP:XMP-exif] DateTimeDigitized : 2017:03:29 12:49:35
[XMP:XMP-exif] DateTimeOriginal : 2017:03:29 12:49:35
[XMP:XMP-xmp] MetadataDate : 2017:10:24 18:12:06+02:00
[XMP:XMP-xmp] ModifyDate : 2017:10:24 18:12:06+02:00
[Composite] SubSecCreateDate : 2017:03:29 13:49:35.59
[Composite] SubSecDateTimeOriginal : 2017:03:29 12:49:35.59
[Composite] SubSecModifyDate : 2017:10:24 18:12:06+02:00

May expectation is that all time fields are changed to "13:49:35.59" as in the green field.

Mario · October 24, 2017, 06:43:04 PM

I cannot tell why Gimp or PS change this date and time.
Gimp is a mainly Linux image editor and I have no idea about how and which metadata it supports.
CS3 is old.

I can tell that shifting the date and time in IMatch produces the correct result in the file. See my data above.
Maybe the metadata in the file is broken in some way. Strip it completely and then rebuild it with ExifTool if you must.
Such issues often result from different time zone handling in different applications. You should only manipulate metadata in one application.
IMatch uses ExifTool to read and write metadata and ExifTool is the reference.

KonradTP · October 24, 2017, 08:00:33 PM

Quote from: Mario on October 24, 2017, 06:43:04 PM
I cannot tell why Gimp or PS change this date and time.
Gimp is a mainly Linux image editor and I have no idea about how and which metadata it supports.
CS3 is old. ...

This is a misunderstanding.
Neither PS nor Gimp have changed the date/time fields as listed by the ExifTool Command Processor.

I have pointed out that the IMATCH "Modify time +1" tool works correctly, if the file is not edited (see file #2 and the correctly changed time fields)

I have changed using PS the picture itself in my test (made it brighter) and then I wrote it back to disk (#3).
I cannot see anything wrong in these time fields looking at file #3.

I made a copy of this changed file (using IMATCH) and tried to modify the time +1 hour (result is file #4)

after editing the original file with Photoshop (result is file #3)
[EXIF:ExifIFD] DateTimeOriginal : 2017:03:29 12:49:35
[EXIF:ExifIFD] CreateDate : 2017:03:29 12:49:35
the field
[XMP:XMP-exif] DateTimeDigitized : 2017:03:29 12:49:35+02:00
was added, but with the same time

The problem comes by using the +1 hour tool in IMATCH on a copy of this file #3 (see #4):
[EXIF:ExifIFD] CreateDate : 2017:03:29 13:49:35
[XMP:XMP-exif] DateTimeDigitized : 2017:03:29 12:49:35+02:00
[XMP:XMP-exif] DateTimeOriginal : 2017:03:29 12:49:35+02:00
[XMP:XMP-xmp] CreateDate : 2017:03:29 13:49:35+02:00

I interpret "13:49:35+02:00" as the correct UTC + 2 time in my German time zone after the modify +1 hour, right?
So I see inconsistent hour values after the IMATCH Modify +1 applied to the file after editing it with PS, while the time fields before the IMATCH command seem to be correct (see fields for file #3)

I'm sure that both programs, PS and Gimp, do something wrong to the metadata, but it doesn't show up in the "list date/time" of the ExifTool Command Processor.

BTW, I think that Adobe Creative Cloud is too expensive for hobby photographers.
I do not want to pay a high monthly fee like others.
I can live with my old PS CS3 for now and consider to the free Gimp when I cannot run CS3 on later Windows versions.

Mario · October 24, 2017, 08:27:56 PM

I still don't see what I should do here.
You are mapping the EXIF timestamps multiple times into XMP using your peculiar workfow. And this causes a mess with the time zones. Just don't do this. EXIF to XMP mapping with respect to non UTC timezones is messy a best, you your workflow forces IMatch to do this multiple times. You shift timestamps, you import EXIF into XMP, you export XMP to XMP, you open your file in CS which rewrites the metadata, then you do the import and mapping all over again. This sounds like a recipe for problems to me.

I recommend you correct your timestamps once, once when you are finished editing your files.
See also the extended notes on EXIF date and time mapping and Metadata Working Group compliance in the IMatch help.

KonradTP · October 24, 2017, 09:13:05 PM

I give up.
I'm NOT mapping XMP fields multiple times, at all.

This is not a peculiar work flow.
I had just made an example that after ANY usual edit done by PS CS3 the time stamps look OK, but afterwards the modify +1 hour in the IMATCH tool has problems.
With my #1 and #2 I just wanted to show that everything is as expected if I use use the IMATCH Modify Date and Time before any editing.
I guess, you are still misunderstanding what I have done.
File #1 is a copy of the original.
File #2 is the result of a Modify Time +1 hour
#1 and #2 time stamps show the OK case. End of this part of the example.

Another copy of the original file is edited by PS resulting in file #3.
The problem is just the inconsistency shown by file #4 (after PS3 editing of the picture and after Modify Time +1 hour done to file #3)

What is so hard to understand here?

I have said hours ago, that my workaround (set the correct time stamps before any editing by PS) is acceptable and I added that I still do not understand why the IMATCH modify date/time does not work correctly after such editing.

This is all.

What is wrong with a workflow like this?
1. Copy the file from the camera card
2. Edit the picture with usual tools on your computer - nothing is done to the original time stamps by me explicitly - the time stamps seem to be OK using the ExifTool
3. Recognize that you need to modify the time stamps
4. Modify the time stamps with the recommended tool

I'm just pointing out that this doesn't work if in step 2 certain programs are used (Photoshop CS3 or Gimp 2.

It is not a big deal anymore since I have found the "workaround".
Thanks for trying to help.

Mario · October 24, 2017, 10:33:27 PM

QuoteI'm NOT mapping XMP fields multiple times, at all.

Way I see it, you do.
You import the file into IMatch. This maps EXIF into XMP.
Now you change the EXIF timestamps. This causes a re-import, again mapping EXIF into XMP.
Now you change the file in CS or GIMP. Which messes up one of the timestamp (CreateDate) for some reason.
Changing a file in an external application causes a re-import into IMatch, mapping EXIF to XMP again.

I tried your sample file.
I successfully shifted the date and time by one hour in IMatch.
The date and time in the file is correct, as well as the XMP generated by ExifTool.
So, IMatch / ExifTool seem to do the proper job as far as I can tell.

I don't have CS3 or GIMP to reproduce the behavior you see, sorry.
In general, messing with EXIF timestamps often causes grief because of time zone problems. Known problem. One of the many flaws in legacy EXIF. Hence, best to process the metadata only once, in IMatch.

KonradTP · October 24, 2017, 11:19:49 PM

Quote from: Mario on October 24, 2017, 10:33:27 PM
QuoteI'm NOT mapping XMP fields multiple times, at all.

Way I see it, you do.
You import the file into IMatch. This maps EXIF into XMP.
Now you change the EXIF timestamps. This causes a re-import, again mapping EXIF into XMP.
Now you change the file in CS or GIMP. Which messes up one of the timestamp (CreateDate) for some reason.
Changing a file in an external application causes a re-import into IMatch, mapping EXIF to XMP again.

No, this is not what I do, exactly.
Forget everything about my #1 and #2 files.(There is no flow from #2 onwards. #1 and #2 were just my proof that things are as expected without interference of PS)

Have a look at the few steps of my problem case:

I had written above:
#3= copy of #1; afterwards changed and rewritten by Adobe Photoshop CS3

#4= copy of #3; afterwards: Modify EXIF Date and Time +1 hour

I start with a copy of the original file in my file system.
Import this to IMATCH.
Edit it in PS just making the picture a bit brighter, not doing anything explicitly to time stamps.
Write the file by PS.
Rescan the file in IMATCH.
This is my #3.
List timestamps using the ExifTool Command Processor.
Do you see anything wrong with them?
I'm sure that something got messed up in the metadata by PS, but it is not visible for me in the ExifTool Command Processor output

Now I make a copy of #3 file using IMATCH (CTRL C; CTRL V in the test folder).
On this copy I perform the Modify Date and Time + 1 hour.
This is my file #4
Now I list Date and Time for #4 and see inconsistent time stamps.

There should be a reasonable explanation why the ExifTool Command Processor shows correct (original) time stamps after the PS edit, which cannot be modified by the Modify Data and Time tool consistently afterwards.

Mario · October 25, 2017, 08:48:39 AM

I have no idea. I tried your sample file yesterday already and I could shift the date and time without problems, even multiple times.

KonradTP · October 25, 2017, 08:00:43 PM

Quote from: Mario on October 25, 2017, 08:48:39 AM
I have no idea. I tried your sample file yesterday already and I could shift the date and time without problems, even multiple times.

Do I understand this correctly:
You have downloaded my file #3 and could Modify Time +1 hour?
Could you show the output of List Date and Time, please?

If so, this would mean that something is strange on my German Windows 10 laptop

, possibly regarding time zone.

Mario · October 25, 2017, 08:55:19 PM

I used the "original file, copied from camera".
IMatch is not responsible for what the legacy Photoshop version does with the metadata. If loading and re-saving the file in CS3 causes the problem, chances are that CS3 is the problem. Not IMatch. I have tried with the current versions of PS and Lr and they don't show the problem.