Lichtfaktor, found this crew some times ago after i started light writing which influenced by pika-pika. With using an exposure of about ten-to-thirty seconds, tripod, glowsticks, flashlights, reflectors, and even torches use to create the light writings. What Lichtfaktor did is the cleanest light writing for what i have seen so far, amazing work.
check out their
stop motion video at:- http://www.youtube.com/lichtfaktorcrew