Gee, favorite? Whatever is at hand and works.

Tough spun is easy to clip to barndoors and doesn't melt. Always some of that in the kit. A white ceiling if it's handy. Bouncing off 4x4' or 4x8' sheets of foam-core if it's a larger shoot with c-stands at hand. There's always a 5-in-1 reflector or two in the kit, which can be used as (dense) diffusion or as a reflector. Baker's parchment if I'm at the grocery store. Whatever.

My favorite "new" discovery is the Rifa. The 44 is a little small for my taste, I like the 55 because it has a nice "wrap" for faces from a good working distance. Sets up so much faster and fewer parts than a chimera.

I have not tried this but it is used in one of the local cable studios.

Furnace Filter

Its non flamable and has lots of layers so you can subtract or add on as needed.

Rifa
 

Seth,

The 44 is small, but I do a lot of quick interviews, and for that purpose, it is useful. I agree that overall the 55 does the job. I do love the quick set up time.

A 6'x6' or larger frame with a silk and a few 1k's. It can take a bit to haul and set-up, and you need to have the power but the large area can provide a wonderful wrap-around for the wider medium shots and interviewer plus interviewee shots as well as close-ups.

I fear that I may be a diffusion junkie. There sure are a lot of choices out there, and many of them overlap. I love playing with them though. Especially those that provide directionality or additional character to the light.
If I was going to have just a few, I'd probably pick: 216, 251, Opal, Hampshire Frost. For exteriors, Tough Spun or one of the "silent" varients would be handy. This ignores the categories of other forms of diffusion such as softboxes, silks, bounces, etc.

What exactly is "tough spun" and where can one buy some?

P.S. Never mind, I found it on B&H. But there are like a dozen different versions: is there a standard filter number for indoor-balanced light temperature?
http://www.bhphotovideo.com/bnh/cont...shs=tough+spun

Tough Spun is from Rosco, one of the leading gel makers.

They make Roscolux Tough Spun, branded for the theater market, and Cinegel Tough Spun for film and video. I think there are more densities available in Cinegel.

Cinegel:
3006 - full
3007 - light (this is most popular)
3022 - quarter

It's not a total diffuser, more of a softener, nice for taming the hard look of light out of an open face instrument like a Lowel Omni or Tota, or an Arrilite. It doesn't change color temp of your lights, nor does a particular light temp need to be matched with a particular spun. You'd probably buy a 20x24" sheet of 3007 to see if you liked it, for small lights it could be quartered for clipping to barn doors.

Info from Rosco at http://www.rosco.com/us/filters/cine...=so&display=17

A good source for individual sheets is www.filmtools.com.
They have a broad collection of diffusion and gels by the sheet. For small instruments, or small jobs, that's the way to go.
Last time I was there, they only had Lee filters online, but Lee makes Tough Spun as well. It's a high-temperature, non-yellowing spun polyester, and it feels like a fabric. Seth is right, it's more of a softener than a full diffusion, and sometimes it is just the right answer.