Classic Scrim Front Light/Back Light Trick

[Chris Chapman]

Been a long time since I've had to properly light a scrim and we have just added one to our inventory. I'm having some problems getting the classic scrim illusion of front lighting the scrim for maximum opacity and then back lighting for transparency to work right.

I'm getting pretty good opacity when I down light on the scrim with 1K Fresnels, but am also getting okay results side lighting it to pick up the weave of the scrim better.

Tech is breathing down my throat, so if I hav to add trees to SL & SR to get a side light wash I need to do it in the next 24 hours.

WHich angle has worked best for you, side light or down light on a scrim to make it NOT transparent?

-Chris

 

[icewolf08]

It is actually a very common misconception that in order to opaque a scrim you use front light. Front light that hits the scrim from straight on to shallow angles will pass through the scrim and illuminate what is behind it, thus allowing you to see through the scrim. In general you need to light from steep or sharp angles to the scrim in order to get it to opaque. This works because the steeper the angle in relation to the scrim, the less light that passes through the scrim. This is why your top light idea works well. The goal, when trying to opaque a scrim is to eliminate or minimize the amount of light that is upstage of the scrim. So, your best bet is any steep angle light to the scrim be it top, side or front. You also might consider using templates to "scrape" the scrim and add some texture.

 

[gafftaper]

Also note even with the best lighting, it's never 100% opaque and it's typical to do the trick with lights then quickly slip in a black curtain behind the scrim to back it up. Or in the opposite direction sneak a curtain out at the last second before you do the reveal. Even when properly lit if the audience is sitting looking at the curtain very long they will realize they can see right through it.