Shaping Light — Flags, Nets, Silks, Diffusion, Grids and Bounce

• Flag — A rectangular frame covered in black fabric. Use it to block light hitting the lens, or to keep light from spilling onto walls and backgrounds.
• Cutter — A long, narrow flag. Use it when you need to cut a long band of light, such as across the top of a background.
• Floppy — A large flag with an extra panel that folds out. Folded, it’s a regular flag; unfolded, it blocks twice the area.
• Distance and edge — A flag close to the light gives a soft shadow edge; the closer it is to the lit subject, the crisper the edge.

A net is a frame covered in mesh. It lowers brightness while keeping the light’s direction and quality nearly the same, which helps when moving the light or changing its output is hard.

• Single net — One layer of mesh, about 1/2 stop less.
• Double net — Two layers, about 1 stop less.
• Open-ended net — One side of the frame has no edge, so the border shows less in the image. Use it to darken only the part closest to the light and even out brightness from front to back.

The exact reduction varies a little with the mesh material and distance. If you need a precise value, measure before and after with a light meter.

Silks and diffusion let light through while scattering it in all directions, making the source bigger. Heavier diffusion is softer but cuts more light. Strengths are often called full, half and quarter.

• Diffusion gel — A thin film you clip in front of a light or onto a frame. Each filter manufacturer has its own numbering, and widely used numbers such as 216 (full), 250 (half) and 251 (quarter) are sometimes used on set as shorthand for strength.
• Silk — White fabric stretched on a frame. Fly it wide over the actors under midday sun to turn harsh sunlight soft.
• Frame sizes — Named by side length in feet: 4×4, 6×6, 8×8, 12×12, 20×20. Large frames catch the wind like a sail, so pay special attention to stand weight and tie-downs.

Softboxes are soft, but their light spreads everywhere and easily spills onto the background. A fabric grid (egg crate) on the front concentrates the light forward and cuts side spill. A skirt is black fabric wrapped around a softbox or lantern to block light in one direction. It’s great in small rooms to keep light off the walls.

• White reflector — Returns light softly to gently fill shadows.
• Silver reflector — Returns light harder and stronger. It reaches farther but can be dazzling.
• Foam board — A light, easy-to-find white board. Mount it on a stand as a bounce key or fill. Paint one side black and it doubles as negative fill.
• Negative fill — Placing black fabric or board close to one side of the subject to remove light bouncing in from the surroundings. In rooms with lots of white walls, it brings back shape to the face.
• Bounce lighting — Aim a light at a ceiling, wall or board and use the reflected light. It spreads wide, but picks up the color of the surface, so choose a white one.