An interview with the excellent Lichtfaktor Crew is on Color Lovers Blog:

COLOURlovers: What drew you to become light graffiti artists?

LICHTFAKTOR: As VJs, we were used to film and because we are all into graffiti it was only a small step. This is the reason why our light-paintings are always moving.

CL: What was it like starting out, and how did you get to where you are today?

LF: We needed content for a 360° projection. This was the first time we used this technique because it just fit so well with the theme of the event (energy in motion). We are still at the beginning, and we know that so much more is possible with lightwriting. We want to explore new ways of expression in urban culture.

CL: What are some of your favourite creations?

LF: We like it when the surroundings are well-integrated into the picture. We also like the abstract light-graffiti stuff, and we want to get deeper into that style.

CL: Do you prefer to work with certain devices, mediums, or places? Do you prefer certain colours?

LF: We like the contrasts between different light sources, like xenon and its nice golden look. LEDs make thin, precise lines and cold cathodes are doing this fatcab style. We put lenses and other different things on the flashlights to get different shapes and colours, or use multiple LEDs and colour filters … we like green, pink, magenta.

I suggest you check it out here