Hi! I was about to suggest that you paint the door opening a contrasting color, but since the corners are round it would not look good. What I think would be the best would be to paint each color to the center of the jamb. Draw a pencil line, or use a chalk line where you want the transition between the two colors, and then use painter's tape (not the cheap masking tape, its adhesive is too strong and might lift up paint when you remove it) to mask one side of the line. Remove the tape as soon as you are finished painting. Wait a full day to allow the paint to dry thoroughly (two days with oil-based paint) and apply the painter's tape to the other side of the line. You'll end up with a beautiful crisp line in the middle of the jamb and it will look great from either side of the door. Hope this helps you.