Another way...take your invitation. Above your top most layer, select your rectangle tool and draw a rectangle. Then add a new blank layer. On your new layer, INVERSE, then Edit Fill with your color. That way you keep your orginal size and have you have a sharp border. Now that might not work if you don't have the extra room to play with on your invitation. (There are other cool things you can do with a mask and the displace filter also). Have fun.