Blackwrap is invaluable when you’re lighting a scene—and the cheaper your lighting gear, the more you probably need it. It’s sort of a Swiss Army knife of lighting—filling a lot of jobs. Just about any time that you’re working with a hot light, and you don’t have the right tool in your kit, blackwrap is what’s gonna save your butt.
For something so useful, it’s surprising that it’s often missing from very low-budget shoots. (But never missing from a pro shoot.) Blackwrap is basically aluminum foil that’s been sprayed with a matte black paint to keep it from bouncing weird reflections all over the set. You can bend it to any shape and put it right on a light without worrying about it catching fire. It’s a great way to block off any stray light that slips through. But it’s crazy expensive for tin foil—it costs 30 bucks a roll So, a lot of people skimp. But you should bite the bullet, buy a roll, and use it—and re-use it—judiciously. Because it’s awesome.