Check-raise bluff effectiveness on the river?

[Logik]

Under what conditions is it +EV to check-raise bluff the river?

On a scare board?
Against a weak tight player?
Against a tight aggressive player?
Against a loose aggressive player?
Against a weak loose player?

I have an image as a passive/aggressive tight player. Because the looser players try to push me around, I tend to slowplay my hands more because usually they respect my raises much more, and thus any action from me usually results in folds.

I play mainly home games, some casino, and venturing now into online.