Can someone tell me what exactly the difference between nets
and scrims as far as the quality of the light passing through
it? I know that nets give you more flexibility regarding what
part of the light's throw you're choosing to knock down, but
I'm more interested in knowing how they effect the light itself.
Thomas wrote :
>Can someone tell me what exactly the difference between nets and >scrims as far as the quality of the light passing through it?
Golly, that's an unusual question which I feel unprepared to answer with authority. That said, I'll put in my two cents worth and say that barring some kind of scientific measurement, the difference between the two is so minimal as to be practically imperceptible.
If you start the net less than a few inches from the object being shot, then further approach the net to the object being shot, there will eventually be a point when you begin to perceive the shadows of the individual strands of the net. But you would have to be very close. Using a scrim in the light itself this would not happen, assuming the light always stays the same distance from the object being shot.
Both the net and the scrim would "break up" the light, even to the smallest degree, resulting in a slightly softer light. I wouldn't have a clue which of the two would soften more.
Gaffer / New York City
Nets and scrims do alter the light's characteristics ever
so slightly, and like Piotr said the difference between the
two is practically imperceptible. I know a certain DP who
refuses to let his electricians use scrims, only ND gels on
the lights because if he wants a hard light he doesn't want
*anything* altering the light's quality. Overkill and impractical
in my opinion.
Los Angeles,CA and Vilnius, Lithuania
The scrim, a round frame with a wire screen of differing densities,
inserted into a holder directly attached to the lamp, is used
to control the overall intensity of particular lamp. The net,
a wire frame with a cloth net of various densities stretched
over it, is used to control the intensity of light on a specific
area of the set.
Nets are held in stands and there is much finer control possible with the placement of the net, ie : To flag the light off a particular piece of the wall or a set piece, to reduce the brightness of a shirt while leaving the face of an actor in the clear, by varying the distance of the net from the light and the set one can make a harder or softer delineation etc.
As for the quality of the light, neither is designed to diffuse the light specifically, (the difference between the two is negligible), rather to reduce the brightness. To control the quality of the light use the many different types of 'diffusion' ... but that is another post.
Ed Colman, President SuperDailies, Inc.
Cinematographer Supervised Video Dailies
I think nets diffuse hard Fresnel light ever so slightly,
while keeping it hard. I know a certain DP who uses lavenders
(1/4 stop net) on all hard frontal talent lights to take the
hard edge off. He came up as a gaffer in a time when hard
light was de rigeur.
Scrims also cause the light to scatter as the wire glows.
My gaffer used some scrims on a Source 4 a while back and
it took a while to figure out where the extra shadows were
Turned out the scrims became a significant light source.
Art Adams, DP [film|hdtv|sdtv]
Mountain View, California - "Silicon Valley"