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-   -   Need floodlight color balancing assistance (http://www.dvinfo.net/forum/photon-management/13149-need-floodlight-color-balancing-assistance.html)

Hugh DiMauro August 12th, 2003 07:30 AM

Need floodlight color balancing assistance
I want to balance my tungsten 650 watt floodlights to use for outdoor fill light. Can anybody tell me what kind of "blue" gel to use for this? I once saw a Hollywood production team use a Lowell type light with a blue cellophane material taped over the front. Where can I get this blue cellophane gel material and is there any special grading of it?

Charles Papert August 12th, 2003 09:44 AM

It's called CTB (color temperature blue), and various manufacturers make it. Try Rosco, Lee and GAM. Full CTB will correct the tungsten light to 5600 degrees which is average daylight. It will knock down the intensity of your light substantially, however. One compromise is to use a 1/2 CTB gel, which will only correct halfway but allow more light transmission. The result will be a warmer light on the actors, which may be desirable (sort of like a late afternoon sun). CTB is available in multiple gradings, from full down to 1/8th. Its companion is CTO, which converts daylight to tungsten, mostly used for gelling windows or to warm up tungsten light for various effects. Having a few sheets of full, 1/2 and 1/4 CTO and CTB in your kit as well as some diffusion will equip you nicely. However, never tape gels to the barn doors. Use clothespins, or paper clips in a pinch. Tape will melt and/or burn.

Hugh DiMauro August 12th, 2003 10:11 AM


Thank you for the prompt reply! I just purchased a Lee 12" by 12" CTB tungsten to daylight filter package. But I need clarification: As far as attaching the gel to the light itself, what concerns should I have in regards to gel-to-lamp distance and fire prevention? Also, how many times are the gels reusable and should I make light frames for them? Any attachment to light hints in detail?

Charles Papert August 12th, 2003 10:41 AM

The gel is designed to mount close to the lights. If your lights have barndoors, you should not have problems clipping the gel to them. Setting the light to the "spot" setting (narrowest beam, if your light has a focus knob) will increase the likeliness of the gel discoloring and eventually melting through, but have no fear about flammability, the gels are meant to be used in this way. Given that this doesn't occur, you can re-use the gel many times.

Hugh DiMauro August 12th, 2003 10:51 AM

FABULOUS! I appreciate you taking the time to respond. It isn't every day I get assisance from actual, working cameramen/cinematographers/filmmakers. This will be my very first project where I take the time to color balance instead of cut corners. I have put many hours in rehearsing the talent. I want this film to be my signature piece.

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