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-   -   Gels for matching color temps (https://www.dvinfo.net/forum/photon-management/88209-gels-matching-color-temps.html)

Michael Galvan March 5th, 2007 04:59 PM

Gels for matching color temps
 
I'm shooting something in a week, but I do not have any HMI lighting to match sunlight temperatures ... just a bunch of pro tungsten kits. What kind of gels can I use to make my tungstens emit light tmperature that matches sunlight? I believe it is CTB gels, but is there any kind of specific gels to look for. Also, I may be looking for gels to cover windows to match my tungsten kit ... what kind of gels do I get for that?

Thanks in advance for any help.

Greg Boston March 5th, 2007 05:09 PM

CTB will make tungsten into daylight. CTO will be necessary for windows to match tungsten.

Keep in mind, putting CTB on a tungsten light will cut the output dramatically.

-gb-

Daniel Epstein March 5th, 2007 06:58 PM

Greg is correct about CTB and CTO. I usually don't try and match the Tungsten lights fully to the day light usually using 1/2 CTB and sometimes 1/4 CTB. Playing with the white balance and letting the outside go a little blue often works better than cooking the subject with full blue tungsten. Bring the highest wattage bulbs for your fixtures if you are going to put CTB on them
As for gelling the windows 85 N6 and 85N9 are pretty useful but you should also get some straight ND in case you need to double the ND. Be warned the 85 CTO with ND option tends to look orange/yellow to my eye so I tend to try straight ND and match my lights to the daylight. (Lately I have been using straight ND and Diva Kino Flos with daylight bulbs.)
Direct sunlight on the back ground is going to be difficult to match with Tungsten units. Are you sure you can't rent an HMI or two for the day.

Ralph Keyser March 6th, 2007 10:51 AM

Good advice here. I tend to do as Daniel does and compromise with 1/2 CTB since the light loss with full CTB is pretty close to 2 full stops. White balanced to the corrected tungsten, the sunlight still looks blue, but not obnoxiously so.

One other thing to consider is that, depending on what you are shooting, you might be able to use Kino Flos to get daylight temp light. They aren't as all-around useful as HMIs, but they are usually much cheaper to rent.

Heiko Saele March 14th, 2007 07:33 PM

Full CTB can be a lot more blue than your average daylight...
I white balanced a Lee Full CTB with a 3500K halogen light and a Sony DXC D30P and it said "7000K", with a Lee 1/2 CTB it said "4900K" - now see what's closer to 5600K...
Well, the Kelvin rating of the DXC D30P isn't any kind of norm, I guess it's off in any kind of direction, but the difference is still visible.

From experience and looks (don't underestimate on what you actually see with your own eyes!) I think the Lee 3/4 CTB is the most accurate match of normal daylight, thus making the Lee 1/2 CTB a viable option for matching daylight (with a touch of yellow, which usually isn't that bad)


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