Diffusion

harryprayiv · August 11, 2004

Hi there. I am trying to compile a list of all of the different kinds of diffusion you guys have worked with. Of course, I could go to the Lee or Rosco web site to find out about this, but I wanted to see how each of you use each kind of diffusion that you describe.

Here's the list of kinds and descriptions of kinds that I have worked with....

216 (VERY VERY common. To me, it yields an almost similar look to a silk)
250 (denser than 215 and useful for creating a soft falloff...but then again, so are all of them)
Hampshire (foggy diffusion that spreads out the light ever so slightly)
Soft Spun (a kind of diffusion that I used only on TV sets. does similar things to silks)
Cosmetic (has a reddish look to it that's good for human flesh tones and has a similar density to hampshire...I've never seen it on a film set, but used it all the time on TV lighting..probably because of the odd effects it has on color temperature)
Opal (the thinnest kind of diffusion I've worked with...does just enough diffusing to maintain a harder look than others)

Michael Nash · August 12, 2004

A good way to learn the diffusion types is to pick up swatch books from the various gel manufacturers (Lee, Rosco, GAM, Formatt). But then you'll still need to practice using them to get used to what they do. Also, there are always new items coming out, and little-used items that enjoy brief popularity.

The most common you'll find on 4'x4' frames are Opal Frost, 250, and 216, going from lightest to heaviest. Hampshire Frost is lighter than Opal, and 251 is lighter than 250. There are different strengths of grid cloth that can overlap the densities of 250 to 216. There are also things like Highlight and Soft Frost (in different densities) that have their own characteristics.

Silks are different in that they create a double shadow; a hard shadow and a soft one at the same time. There are 1/4 and China silks for more transmission and less light loss; Bleached and unbleached muslin for more more diffusion.

Really, the variety and application is almost endless. I happened onto a neat trick with a 10K and a 12'x12' frame of 1/2 grid cloth where I realized that the fabric kicked back almost the same amount of light as it let through -- meaning I could create an almost 360 degree even soft source with this material.

I just finished gaffing a show with a European DP who requested things like "1/2 spun" and "1/4 trace" which simply don't exist in America, yet I knew what he wanted and was able to give him an equivalent from more common off-the-shelf items.

harryprayiv · August 12, 2004

Thanks for the reply. Do you know of any places where I can find a wealth of this information in one place. i want to know what each diffusion does BEFORE I get on set, so I don't waste a lot of time in my lighting setups sitting there experimenting. When I work for myself doing lighting though, I usually take as much time as I want for setups and in turn, learn a lot.

Carlos M. Icaza · August 12, 2004

I know the feeling of having to learn on the set. The only way I done it, is setting up the lights at my small studio and then flagging, silking, gelling, scrimming and determining the look and feel of each item. I usually light meter the space I am shooting at before and after to compare how much light is cut when I flag/silk/gel/scrim... then make lots of notes.

That's the only way I done it, I only wish I have more time and more gels and more... :lol:

The rosco website and some of the other websites around (google them) have information on them and so does reading lots from the AC magazine.

C.-

Sam Wells · August 12, 2004

I think the replies have cataloged it pretty well.

Sometimes, in actual practice, the differences are less than profound.

I confess to having clipped a carefully selected sheet or two of "what's lying nearby" on a light more than once.

I don't know how much you can learn in the abstract, subjects in filming situations have their own diffuse/specular character, color, etc

-Sam

Michael Nash · August 13, 2004

I don't know how much you can learn in the abstract, subjects in filming situations have their own diffuse/specular character, color, etc

That's a good way of putting it. There's no substitute for experience and practice. You have to put in the time trying things and learning through doing.