Do not begin by guessing exact dates
Sort the scans into groups first: album, envelope, household, decade, or event. A defensible year is better than a made-up day and month. Record uncertainty in a caption instead of presenting it as fact.
Use a consistent dating rule
If several pictures are known only to be from 1968, choose a documented convention for the unknown month and day. Apply it consistently and note the rule in your project records. Consistency makes later corrections much easier.
Write captions people can search
Start with names, place, occasion, and approximate date. “Marta and Lewis Smith, Cleveland, around 1968” will help a relative far more than “old family photo.” Put uncertain identifications in plain language.
A practical batch
- Keep untouched master scans in a separate folder.
- Group related images before editing.
- Correct dates for one known group at a time.
- Add short captions and creator or copyright information where appropriate.
- Export edited copies and spot-check them in Photos.
- Back up both the masters and the organized copies.
Ask relatives while you can. Software can change a date, but it cannot recover a name no one remembers.
Preserve the evidence around the photo
Scan the back when it contains handwriting, a studio stamp, or a date. Photograph the album page before removing prints. Those clues may be more valuable than any metadata field you add later.