My hallway is now a giant chalkboard.
Strobist: SB-900 on camera, angled up and back, bounced for fill. Remote SB-800 held by Jack on the stairs angled down at right wall. SB-600 on stand around corner, aimed at far back wall for rear fill. Ambient sunlight through the kitchen door.
Details: Wall was created using 1 gallon of paint, two cups of white unsanded tile grout, mixed to grout instructions, half gallon at a time. We edged and filled with a roller. Two coats. I used 9 chalk sticks to prime the wall.