Although the Photos app for macOS has improved considerably since its introduction several years ago, it still has some clunky features that you should be careful touching because they could be painful to fix. The worst of them is: ‘Image > Set date and time’.
When used carefully, it is a way to fix the wrong date and time on a single photo or to adjust the offset of a group of photos. Let’s say you have a camera set to the wrong time zone, date, or time of day, or all three.
This was a common problem with older cameras, which would restart at an arbitrary time if they ran out of battery. But today it’s easy to do: just travel a few time zones or inadvertently set the date incorrectly.
You may also want to read: How to edit photos with your Mac computer.
This lag is revealed in Photos when images from different sources, like a camera and the iPhone, are put together and incorrectly interleaved. Or they’re just in the wrong place: hours, days, or years away from what you expect.
Set date and time allows you to correct this. Select a group of images and videos that are all wrong by the same amount, such as 2 months, 5 hours, and 1 time zone. In the dialog box, enter the first correct date and time; you can also change the time zone. Apple then adjusts all images and videos by that factor, and sets all media to a different time zone if you’ve selected one.
But what would happen if the wrong information was entered? A reader sent the pictures of him some 2,000 years into the future, all 27,000. Apple does not offer the ability to undo the operation: there is no way to click and reverse it.
The best solution is to reverse the offset. The Adjust Date and Time function does not adjust all selected media to a single date and time, but rather adjusts all images by the same degree as the difference between the original time and the adjusted time of the first image.
Imagine you have three photos in a selection taken in 1990 on January 14 at 5:30 PM, January 15 at 10:30 AM, and January 20 at 8:01 PM. Set the adjusted date and time of the first image to April 20, 1983, 8:30 pm, and those images would now be stamped in 1983 on April 20, 8:30 pm, April 21, 1 :30 p.m., and April 26 at 11:01 p.m. Changing them back would be a matter of selecting the same set and entering the original capture time: January 14, 1990, 5:30 PM.
Here’s how to reset the offset:
- Find the set of images you’ve set to the wrong offset if it’s not the entire library. You can use smart albums to identify a set of images that is outside of the date range you normally handle, for example. (Choose: ‘File > New Smart Album’ and set the criteria for each date range).
- Select all the supports in the set you want to invert the offset: ‘Edit > Select’ all or press ‘Command-A’. (See the note just below.)
- Choose ‘Image > Set date and time’. Notice that Photos shows you the first image of the selected set.
- For the adjusted time, enter the correct time for that image. (Don’t know the date and time? See below.) Click ‘Set’. The Photos app will now correct all images.
If after following step 2 above, Photos does not allow you to choose ‘Set date and time’ in step 3 if you have any referenced media in the selection. If there are any included, you have to correct or exclude them. Either create a new Smart Album that excludes them or import those referenced images and videos into your library.
If you don’t know the correct time of the image in step 4, follow these steps:
- Select the image in Photos.
- Select ‘File > Export > Export Original Unmodified’ for 1 photo.
- Click ‘Export’ and browse to a location to save it.
- Open the image in ‘Preview’.
- Choose ‘Tools > Show Inspector’.
- Click on the ‘info’ tab and click on the ‘EXIF’ button.
- Find the information noted for ‘Original Date Time or similar’ and write it down.
Yes, it’s ironic that you have to open another Apple app to get the information you need.
If the above is too finicky for you, if you find that you have too many different sets of offset images, or if there is some worse weirdness that you think might be some sort of fix, you can also fall back on a backup.
However, if iCloud Photos is turned on, backup can only work if the iCloud setting in ‘Photos > Preferences > iCloud’ is set to download full-resolution images, as described in “How to Back Up Photos”. local synced iCloud Photos library.” If iCloud Photos is set to Optimized, there’s no way to revert it.
Original article published in English on our sister website Macworld USA.
