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How can one bulk time-shift the creation date of JPG images? (OS X)

How can one bulk time-shift the creation date of JPG images? (OS X)

I have an unfortunate situation following a vacation. The gist is this: 2 cameras, with Camera #1's clock being two days ahead of Camera #2. Therefore, in (Insert Photo Management Application Here), the photos are interleaved and not in a sensible chronological order. If I could simply move the create date of these images on camera #2 forward enough, then I'll have a fighting chance to actually organize all of these photos.

Asked by: Guest | Views: 229
Total answers/comments: 2
bert [Entry]

"There will be quite a few tools that work on the JPEG EXIF fields.
I have always found Phil Harvey's EXIFTool to be fantastic.

Mac OS X Package: ExifTool-7.98.dmg (1.4 MB).
The OS X package installs the ExifTool command-line application and libraries in /usr/bin.
After installing, type ""exiftool"" in a Terminal window to run exiftool and read the application documentation.

What you are looking for now is,

Date/Time Shift Feature
Have you ever forgotten to set the date/time on your digital camera before taking a bunch of pictures? ExifTool has a time shift feature that makes it easy to apply a batch fix to the timestamps of the images (ie. change the ""Date Picture Taken"" reported by Windows Explorer).

Say for example that your camera clock was reset to 2000:01:01 00:00:00
when you put in a new battery at 2005:11:03 10:48:00.
Then all of the pictures you took subsequently have timestamps that are wrong by
5 years, 10 months, 2 days, 10 hours and 48 minutes.

To fix this, put all of the images in the same directory (""DIR"") and run exiftool,

exiftool ""-DateTimeOriginal+=5:10:2 10:48:0"" DIR
=================^^^^^^^^^^^^^^^^

You need to adjust the incorrectly stamped batch to just two days forward.

Update: Towards working with Create and Modify times for iPhoto,
EXIFTool notes continue at the Date/Time Shift Feature section,

The example above changes only the DateTimeOriginal tag,
but any writable date or time tag can be shifted,
and multiple tags may be written with a single command line.

Commonly, in JPEG images, the DateTimeOriginal, CreateDate and ModifyDate values must all be changed.

For convenience, a shortcut tag called AllDates has been defined to represent these three tags.
So, for example, if you forgot to set your camera clock back 1 hour at the end of daylight savings time in the fall, you can fix the images with:

exiftool ""-AllDates-=1"" DIR
=========^^^

This will roll back all timestamps by 1 hour.
Hopefully, your original files are available for doing this...

Finally, if you have the original meta data corrected,
but with incorrect file time.
You can do the following,

exiftool ""-DateTimeOriginal>FileModifyDate"" DIR
^

This will push the corrected EXIF timestamp to the file modify time."
bert [Entry]

"If iPhoto uses the filesystem date/time, just do this to set it from the EXIF information:

exiftool ""-filemodifydate<datetimeoriginal"" DIR

before importing into iPhoto

No need to screw up your metadata"