Changing EXIF dates/times on multiple photos

killmoms

macrumors 68040
Original poster
Jun 23, 2003
3,722
13
Washington, DC
Okay, so I've got a whole roll of photos in iPhoto from my girlfriend's camera from spring break. Unfortunately, her camera's internal clock was set wrong. Like, a year and one month wrong. And the time was wrong too. So I've got a whole roll of 123 pictures that have incorrect dates and times.

FORTUNATELY, I've got a roll with correct dates and times from another friend who was on break with us, and he took a picture of two of my friends that's almost the same as one my girlfriend took (i.e. they both took a picture almost at the same time). So I've got a photo that gives me a pretty good idea of the "offset" between the incorrect dates/times and the correct ones.

My question is: is there a utility out there that will allow me to batch "add" a certain amount of time to the EXIF data for date/time taken in every single photo that's wrong? The photos span a period of one week, so it'd be convenient to just say "add X months, X days, X hours, X minutes" and apply that to every photo, rather than doing everything by hand. Any suggestions?
 

killmoms

macrumors 68040
Original poster
Jun 23, 2003
3,722
13
Washington, DC
dogbone said:
exiftool is pretty efficient. The exiftool forum is very helpful if you need any assistance.
Thanks for the suggestion! I successfully ran exiftool to adjust the date on the photos in question. One problem though—is there any way I can force iPhoto to "re-read" the EXIF data into the library? I'd like to do it without re-importing, since I have some modified images, some that I don't include in the library anymore, etc. Because, of course, iPhoto has already cached the original dates into its XML database of the photos, so if I look at the info now it reads it from the database, not the actual JPG files. Any tips?
 

dogbone

macrumors 68020
Cless said:
Thanks for the suggestion! I successfully ran exiftool to adjust the date on the photos in question. One problem though—is there any way I can force iPhoto to "re-read" the EXIF data into the library? I'd like to do it without re-importing, since I have some modified images, some that I don't include in the library anymore, etc. Because, of course, iPhoto has already cached the original dates into its XML database of the photos, so if I look at the info now it reads it from the database, not the actual JPG files. Any tips?
Sorry I don't know. Maybe you can remove the cache (and store it somewhere safe in case you need it) and force iPhoto to rebuild. It should be possible but I don't know how.
 

balamw

Moderator
Staff member
Aug 16, 2005
19,368
974
New England
dogbone said:
Sorry I don't know. Maybe you can remove the cache (and store it somewhere safe in case you need it) and force iPhoto to rebuild. It should be possible but I don't know how.
Start iPhoto with option held down to rebuild the library. This might pick up the new EXIF tags.

B