DV101 'A Shot in the Dark': Flavors of Diffusion for Your Video Project

The following is an excerpt from chapter 5 of Jay Holben's book A Shot in the Dark: A Creative DIY Guide to Digital Video Lighting on (Almost) No Budget.

Diffusion
Introducing diffusion media between the light source and the subject is one way to create a soft source. There are many types of diffusion, from the lightest (and most translucent) to the heaviest (most opaque).

The Real Stuff
Professional diffusion media comes in many "flavors," from Hampshire Frost to Tough White diffusion. The more opaque the material, the more it will soften light, but also the more light is lost. Rolls of diffusion generally sell for about $140 for 4' x 25' roll of the material.

The same manufacturers of gels are the primary manufacturers of diffusion materials: Rosco, Lee and GAM. There are three primary groups of diffusion from each of the three manufacturers: frost, spun and grid cloth. Frost diffusion is the most common, and the industry vernacular generally follows the Lee numbering system.

This chart is provided merely as an example of the similar diffusion offerings from these three manufacturers. Practically speaking, all of these types of diffusion are interchangeable; Rosco 3026 can easily be substituted with Lee 216 or GAM 10-80. While these diffusion products are nearly identical, each manufacturer offers additional diffusion choices that are unique to that brand.

	Professional diffusion material on a sheet of black paper to demonstrate the various opacities

Spun diffusion is a more textile-like material that has a natural amorphous fiber pattern to it. It creates a very soft source without reducing the intensity too much. Both Lee and Rosco make spun diffusion (Rosco 3006, 3007 and 3022; Lee 214, 215, 229, 261–265).

Grid cloth is a textile material, almost a rough silk. It can be sewn and used in large sections. It comes in Full (R: 3030, L: 430), Light (R: 3032, L: 432) and 1/4 (R: 3034, L: 434) strengths.

Finally, not offered by any of the gel companies, muslin (which is a thick, canvas-like woven cotton fabric) is often used as a diffusion and/or bounce material. Bleached (white) or unbleached (off-white, which adds a touch of warmth to the bounced light) can create wonderful soft light.

	Diffusion alternatives

All of these are exceptional tools for creating diffusion, but they are expensive. There are, however, many alternatives to these materials that can be just as effective.

Caution:
A major difference between professional diffusion materials and inexpensive alternatives is that the commercial varieties are all flame retardant. They are meant to withstand the high temperatures found close to lights without melting or bursting into flames. All of the alternative materials I'll talk about here are exceptional diffusers, but keep in mind they are not flame retardant. If you use them too close to lighting fixtures, it is very likely they could start a fire. Be cautious, especially when making softboxes, as trapping in the heat with non-retardant materials can be dangerous.

Cheaper Alternatives to Diffusion
Tracing paper is one of the most common diffusion alternatives, and one that is actually used quite often in the professional industry along with the real stuff. Offered in different strengths at any art supply store, and in large rolls, tracing paper is translucent enough to allow light to pass, yet opaque enough to act as an excellent diffuser. Tracing paper is extremely flammable and should never be used in direct contact with any hot lighting fixtures.

Parchment paper is excellent diffusion that is heat resistant (though not flame proof) and can be used closer to hot fixtures with caution. It is commonly available only in 12" to 16" widths, so it's not great for larger diffusion needs.

Bed sheets are also wonderful alternatives to heavier diffusion. A simple white sheet can make a fantastic large diffusion frame. Sheets are available in a variety of thicknesses, thread counts and shades of white, each providing different levels of diffusion. A little experimentation is necessary to find the type that works best for your taste.

Lining fabric is an inexpensive silk-like material intended for the lining of clothes. You can get it at any fabric supply store in white, or off-white to add a little warmth to your fixtures. Stretch it around a frame and you have an instant "silk" to match the expensive silks used in the professional motion picture industry. It sells for about $2 to $4 per yard.

Plastic picnic table liner can also be a good diffuser. Sold in large cuts or rolls, it is incredibly cheap. It's a fairly opaque but thin material that makes for a great heavy diffuser or bounce. Again, keep these well away from any hot lights. This stuff will melt very quickly. It also tears easily and is generally not very robust.

Clear or white Visqueen (polyethylene) is most commonly used as a disposable drop cloth. It's sold in large rolls and is available in the paint department of hardware stores. Again, use caution close to light sources or you'll have a stinky, gooey, melted mess on your hands.

Vinyl shower curtain liners are very white and opaque, so they don't transmit a lot of light, but they can create wonderful soft sources. As with bed sheets, the naturally large size allows for an inexpensive large source if stretched out and filled with light.

A Shot in the Dark is available from amazon.com, barnesandnoble.com, bhphotovideo.com or theasc.com, among many other book retailers.