To start, make sure you have good quality low-tack masking tape on hand (low-tack means it peels off easily without removing any paint).
Use a pencil or chalk to mark out where you want the divide of colours to be. Apply your first colour on the wall extending it slightly past your pencil line. We recommend painting the lighter colour first, so if there are any drips they’ll be easier to cover up when you paint the lower half of the room.
Once the paint has dried, stick down your masking tape over the first layer of paint. We recommend you stick the tape down at one end and then unroll a long length of it, stretching it taut before pressing down firmly. Doing this rather than unrolling it as you stick it down will result in much straighter lines.
The edge of the tape should sit 1 or 2 cm above where the first colour ends. Make sure you paint the second colour over the masking tape line slightly – this will create a crisp line under the tape. To stop any paint from seeping under the tape and spoiling your straight line, only load up your brush with a small amount of paint at a time.
Almost time for the big reveal! To stop the paint peeling off along with the tape, remove the masking tape before the final coat has finished drying. Make sure the paint isn't wet enough to drip before peeling back the tape to reveal a clean line.