I recently saw this DIY light bar on Reddit and it looks really cool for artistically controlling how much light your photographic subject received. In this case it’s a car (a Tesla or some sort I believe).
The results of using selective lighting can be pretty spectacular as evidenced in the picture after the “read more” link. What you see is actually a composition of five photos using this light painting technique. The set of photos that it’s from claims that it will “take some time to perfect the technique.” If that’s a poorly done photo, then I can only imagine what a “good” photo would look like.
As for how the DIY light bar was built, the aforementioned photo set goes through the assembly steps. If I had to summarize it though, the idea is to stuff lots of (600!) LEDs into a length of aluminum channel, paint it black, and add a hand grip and battery pack.
That doesn’t sound that hard, but doing a really good job of it, as was done in this project is no small feat.
The technique of selectively illuminating an object as seen here with a flashlight, light bar, or otherwise, is sometimes known as “light painting.” What I generally call “light graffiti” is also called “light painting,” so there’s some ambiguity there.