You can do it at the content level using the Parental control system and ratings.
Yes, if you'd rather keep things in the same library you could set a parental rating for the contents of the adult folder and set all the accounts that shouldn't see its contents to a lower maximum parental rating. You'd just need to set the rating for that folder manually kn the metadata manager since your photos won't have that in their source info.
I like splitting content into separate libraries based on who needs access and using library controls but I also layer on parental controls. For example my movies are broken out into folders for each user if only that user will watch it or a family folder if multiple people want to see it. Each of those folders is its own library and each user has access to their library plus the family library. On top of that the users have parental controls based on ratings so the smaller kids can't see the R-rated stuff that's in the family library. With this setup all I have to think about when adding more content is how many people want to see kt. If the answer is 1 it goes into the user folder and if it's more than one, the family folder.
Edited by Deathsquirrel, 10 September 2017 - 11:42 AM.