Have you ever noticed how the lighting of a scene will change from shot to shot in a movie? In a scene that takes place outdoors on a sunny day, look at how the shadows change–particularly on the actors’ faces. In the wide, long shot, the faces are in direct sunlight and partially shadowed. However, in the close-up, the face is completely shadowed and perfectly, evenly lit. Faces look good without hard shadows. It’s a more cinematic look than having half of the face in the sun, overexposed, and half shadowed, underexposed. This is accomplished by suspending white, translucent fabric, normally on a frame, over the actors. This shields them from direct sunlight and gives a nice diffused look that makes anything look great. While this may not be the look you should go for in your gritty “Fist Full of Euros” western, there’s no way you’ll get Jenny “from the block” Lopez to do your micro budget film if she’s not going to look beautiful in her close-ups. In many other circumstances, a diffused lighting source is desirable. Not only in exterior day shots, but anytime a softer, more pleasing look is wanted, diffusing light is the way to go. I use heavily diffused light in night shots almost always. When light is scattered, coming from multiple sources at once, shadows are reduced. The larger (and closer) the diffused light source, the more reduced the shadows and the more ‘glowing’ the scene will look. Here I’ll show you how to make a large (almost limitless size) diffuser. I made one 10 feet by 9 feet.

I have no idea what the difference is between a “scrim,” a “light diffuser”, and a “butterfly.” I suspect it has more to do with how it’s used rather than what it is. I use the terms interchangeably. My apologies if it is confusing. Whatever it’s called, the design is very simple: Sew fabric into a big square and build a frame for it.
This is what you’ll need:
•    10 yards white translucent fabric (rip-stop nylon)
•    4 – 10 foot sections of 3/4″ EMT rigid electrical conduit
•    4 heavy duty 90° 3/4″ conduit elbows
•    50ft 1/4″ cotton rope
•    A small or medium grommet kit (sold at a hardware store)
•    A friend with a sewing machine
Start with the big white fabric square. For digital video, I a lighter fabric is important to let as much light through as possible (keeping actor-to-background contrast to a minimum). It also needs to be durable. For this, rip-stop nylon is the fabric of choice. I called all the fabric stores in my area and found prices ranging from 4-6 dollars a yard (39 inches wide). I bought 10 yards, so I cut the fabric in thirds to make 3 ten-foot sections. Then, I found someone to sew it together (if you can’t find anyone, it’ll cost 10-20 bucks to pay someone professionally to do it). Now, put a grommet every two feet around the cloth starting at the corners. Fold the edge of the cloth over three inches before pressing the grommet, as this will reduce tearing (it’s rip-stop nylon, not rip-proof). Optionally, sew the three-inch edge over before you grommet to keep the edges from fraying.
Next, build the frame. The frame should be six inches larger than the dimensions of the cloth square. The conduit can be cut with any number of tools, or ask the hardware store and they’ll probably cut it for free. In a clean, dry, large area, connect the four pieces of conduit using the conduit elbows. Tighten the two set screws on each elbow.
Now attach the cloth square to the frame using the rope. Count the grommets on the cloth square and cut an equal number 18” length pieces of rope. Tie the cloth square off to the frame. Optionally, I like to first “Lark’s Head” knot (see illustration) the rope in half on the grommet so the rope permanently stays on each grommet. When tying to the frame, I tie a regular old shoelace knot, and then double knot it (like my Mom taught me!).

Now put it to use
Suspend the scrim over actors’ heads to give beautiful light. If you have C-stands, it should be easy. If you don’t, there are other ways. You could fasten it to a tree or house and the other side to an 8 ft ladder with sand bags. If there aren’t things to attach it to, use a ladder and have a tall crew member hold it above their head (it’s not heavy at all). Or, probably a better idea, buy more electrical conduit poles and suspend it in the air with those. However it gets suspended, make sure the scrim is well secured to the ground with ropes and steaks. It doesn’t take much wind to lift it away.
Another use is as a diffuser or reflector for a light. Stand the frame vertically. Position the light either behind the scrim to diffuse or at an angle in front to reflect. I like the look of this at night and I use this setup especially when trying to cheat a few extra minutes out of magic hour.
Lastly, use the scrim as a reflector for the sun. Tilt the scrim diagonally in front of the actor, just off screen, and find the ‘sweet spot’ where her face lights up. I used it like this in a dolly shot where two people were walking through a field. We couldn’t setup a stationary lighting, so two crewmembers walked the scrim backwards along with the actors and dolly, keeping light on the faces. It was very effective.

Cost: The fabric is the most expensive part. With fabric and all the hardware supplies, it costs about $60.