Design Are Half-Filters Used in Theater?

[Pynspot]

I'm sitting in photography class right now, and my teacher claims that half filters are used all the time in theatre, even though I'm unaware of any of their use. I'm referring to filters that are amber on top to make a sunset extra-pretty, but I don't know where they would be used onstage.
He says that they're used when taking pictures of scenes, and that they go on individual fixtures (I suppose he's just thinking of color gels).


Am I just unfamiliar with these filters, or is he making stuff up?

 

[rochem]

They're actually used more than you'd expect. In theatre, they're generally referred to as Split Gels. Sometimes it is for reasons like you said, to make the top of a beam of light a different color than the bottom. Other times its just to create a more dimensional light rather than having it be all one color. Check out SplitGel : Mixed Color Split Gels from GAM : Lighting Equipment For Architectural, Specialty & Theatrical Effects for some detailed examples. As far as I know, there's no gel manufacturers that actually sell split gels - they're just made by the individual for each show by cutting two or more gels and taping them together.

 

[shiben]

I love using split gels in the theater. If you are clever, and combine them with a template of some sort, you can get an effect similar to a prismatic glass gobo without having to actually buy one. I find them to look exceptionally good when shot thru haze. Actually, come to think of it, using a pile of them in a ground row might make a cool fire effect...

 

[Lotos]

We use Split Gel's mainly in Gobo washes, to add depth to the light. They work best with random breakups, or geometric shapes, etc...
I keep a large stock of these guys in my gel storage in many combinations of colour, but all have been made on site using two cut gels, and some Clear-to-the-core tape, in a configuration like this:

 

[Pynspot]

Ok thanks. I guess that makes sense. He just explained it a little differently, like you would align the top half to hit a cyc and the bottom half to hit the set. People may even do that, I guess.

 

[Footer]

Ok thanks. I guess that makes sense. He just explained it a little differently, like you would align the top half to hit a cyc and the bottom half to hit the set. People may even do that, I guess.

That does not really work in the world of photometrics. You might get it to kind of work, but the only way to get two perfectly separated colors in a light is to put the color in the gobo slot (glass color).

Otherwise, split gels are really only used for coloring gobo washes or various other effects.