can I restrict public access to my main gallery while still allowing public access to some of the albums inside it?
Thanks

You can give users rights to certain (top-level) albums:
http://www.zenphoto.org/news/an-overview-of-zenphoto-users

thank you for helping. my problem is: when i put a password on the top level gallery, all albums inherit the login/password requirement. I only want the main gallery (index.php) to be password protected. i dont want visitors to have to go through a login (even as guest) to see the albums. is this possible?

Of course that is the sense behind protecting the gallery. You must admit that doing this otherwise is pretty useless...

What you probably want is to use unpublished albums. Those don't appear in any menu or list but are accessible by anyone who knows the link to them. But that is no protection.

aha! Unpublishing the albums is what I wanted to do. Thanks again for the help