Get Straight Paint Lines by Knifing Down Quality Tape Instead of Sealing It

The Problem

The internet's favorite fix for tape bleed is painting over the tape edge with the color underneath before your new color goes on. It works — but it adds a coat, a second brush or roller, cleanup, and a wait, all to fix an edge that was never sealed properly in the first place.

The Technique

1. Start with a quality tape. A standard multi-surface painter's tape (FrogTape green is the common example) covers most walls; delicate-surface versions exist for fresh paint and wallpaper, and some pros prefer washi-style tapes, which are thinner but fussier to handle.
2. Lay your line, then knife the tape edge down with a flexible putty knife. A stiff blade rides over the tape; a flexible one conforms and squeezes the air out from under the edge, giving the adhesive solid contact along the entire line.
3. Paint your finish color immediately. No sacrificial sealing coat, no waiting, no pulling tape against a wet base coat.

The knifed-down edge is what tape adhesive is designed to do — the sealing-coat trick exists to compensate for skipping this step.