To use a V-flat to flag a light, position the black side of the V-flat between the background and the light — black will help absorb the light. Turn on the light’s modeling lamp to see if the light is spilling onto the background. Adjust the V-flat until the background isn’t affected.

Want to learn more? Check out this article, “Modifying light with versatile, extremely portable V-flats”

Get them at V-Flat World