Frog Tape has a special ingredient that turns paint into a gel before it can bleed underneath, so you get supercrisp lines. The medium-strength adhesive won't harm wood finishes, but avoid putting it on wallpaper. Use it outdoors for up to 14 days and indoors for 21. It has a one-year shelf life. About $6, frogtape.comTOH Tip:
"To get the cleanest edge, pull off the masking tape while the paint is still tacky."
—This Old House
master carpenter Norm Abram