It might happen that you shot a lot of photos with a camera that had incorrect date setup, like 01-01-2001 – the date that has been initially set by a manufacturer and had been never adjusted to a correct value.
In same time those photos have correct time distance between each other, because an inner timer of a camera ticks all the way. So if you know an exact(or approximate) day and time when photos were taken, you can use the batch time correction feature to fix dates of all those photos.
Just select one or multiple photos and go to menu Photos->Adjust Date And Time, the dialog appears:
The first photo of selection is called “basic photo”. Provide a new time and date for a basic photo, and timestamps of all other photos will be shifted accordingly.
If you want Phototheca to write new timestamps into EXIF part of metadata within JPEG files, set the check-mark “Modify original files”.
Read more: Correct timestamps | Phototheca User Guide