FYI - we're NOT affiliated to this brand in any way but we just wanted to respond to lots of folk who've been asking about who we use as regards masking tape! The best brand, as we see it is Scotch Blue and we've been using it for years on our TV shows and during magazine editorials etc. Its low adhesion means it peels off perfectly so you get straight edges every time.
So there you have it! Simple stuff... but effective nevertheless!
C et J xx