Search by keyword in MacOS Hidden photos album

Lenold wrote: … "hidden" is an attribute only of files (photos), not of albums.

That's correct. Pictures can be in many albums, so marking a picture as "hidden" makes if invisible in all of its albums-- you don't have to remember, "oops-- did I hide it in the Grand Canyon album, or just in the June '06 album? What albums might I have missed?"

And in Photos a picture doesn't exist as a file.

I've assigned a keyword to certain photos in my "Hidden" album. How do I search for those photos in just the hidden album with that keyword?

Use a Smart Album like this:

You'll have to use a password to open the album, if you have that enabled.

Probably easiest long-term: Create another login, and keep your secrets over there.

Enable Fast User Switching to make swapping logins faster.

You bet! I really just learned that "hidden" was a choice in Smart Albums.