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Greenish tint.

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Dan Asselin
Greenish tint.
on Jun 16, 2009 at 1:24:53 am

Hi;

I'm working with flouresents of 5,000K and unknown CRI. Not surprisingly I have a greenish tinge to my footage. The problem is that there seems to be no way I can eliminate it on Premiere that I find acceptable. Could anyone suggest a colored gel I could use when shooting in order to give myself a chance.

Thanks for any help and sorry if this is too basic a question for this forum but, as Bones used to say to Jim...."darn it Jim I'm an editor and not a cameraman". Or something like that.



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Mark D'Agostino
Re: Greenish tint.
on Jun 16, 2009 at 2:09:44 pm

Hi Dan,
If you're using HMIs add either Rosco Plusgreen or 1/2 Plusgreen to your lights. With tungstens also add either full or 1/2 blue correction to the green. I tend to use the 1/2s since my lights are small and I need all the output I can get and it works just fine.

Several years ago a long time DP who developed lighting correction charts for the ASC manual took the time to test several types of fluorescents and sent me specific corrections for each. It was an amazing gift for which I've always been grateful. His name is David Quaid. Here's what he sent. These give very accurate balances but I usually stick to what I wrote above when time is tight:

The increase/decrease refers to the incident light metering

3200K Tungsten

Cool Whites: plusgreen50,(they don't make this any more though I do still have a roll. It's basically 1/2 blue & plusgreen combined in one gel) *increase 3/4 stop

SP35:1/2blue, 1/2plusgreen, 1/4plusgreen
*decrease 1/3 stop

SPX35: same as SP35

OSRAM FO: same as SP35

SP30: plusgreen, 1/3blue,1/4plusgreen

GE Light White F96T12 LW: 85, plusgreen50, 1/2 plus,
* increase 1/2 stop

GE Metal Halide MVR250/HOR U: plusgreen50, 1/2plusgreen,
1/8plusgreen, 1/8blue

HMI:

Cool Whites: Plusgreen, 1/4 Plusgreen
*Decrease 1/4 stop

SP35: Plusgreen, 1/4CTO, 1/8CTO
*increase 1/4 stop

The alternative, considering you can't remove the fluorescents and replace with Kino tubes is to gel the fluorescents with Minusgreen gel from Rosco. (I happen to use Rosco but you could certainly use whatever brand you prefer).

I hope this helps.




Mark D'Agostino
http://www.synergeticproductions.com


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Dan Asselin
Re: Greenish tint.
on Jun 16, 2009 at 6:42:28 pm

Wow. You're right. That is an an amazing gift. It does help and I very much appreciate your sharing it with me.

Thanks

Dan



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Rick Wise
Re: Greenish tint.
on Jun 16, 2009 at 9:18:09 pm

Remember that there are two very different ways to go when dealing with fluorescents with green spikes (as most do, with the exception of Kino Flos and perhaps a few, very few others.) Either you add green to all the other lights to match the green of the offending fluorescent, or you add minus-green (magenta) to the offending fluorescent(s) so it matches your other lights.

You are dealing with two color axises: magenta-green on one axis, and blue-red (or orange) on the other. Gels to correct for each axis come in strengths beginning with 1/8 through full (1/8, 1/4, 1/2, full.) The color differences between tungsten and daylight units are mainly along the blue-red axis. (Some HMIs can have or can develop some green spiking too.) Fluorescents can be "daylight" or "tungsten" balanced and also almost always have some green spiking. You need to pay attention to both the blue-red axis and the magenta-green axis.

In general, with the situation you described, I'd put 1/4 minus green on the "bad" fluorescents, shoot a test, and if there is still too much green, try 1/2. Etc.

Rick Wise
director of photography
and custom lighting design
Oakland, CA
http://www.RickWiseDP.com
http://www.linkedin.com/in/rwise
email: Rick@RickWiseDP.com


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Dan Asselin
Re: Greenish tint.
on Jun 17, 2009 at 12:37:00 am

Thanks Rick I appreciate your help as well.

Dan



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Mark D'Agostino
Re: Greenish tint.
on Jun 17, 2009 at 2:56:00 pm

Rick's explanation is perfect. The key to what he says is to shoot a test. Different tubes spike green differently and are affected by age. Also, if you've shot someplace and figured it all out don't assume that it will be the same the next time you shoot there. The maintenance guy may have replaced old tubes and may not have chosen the same replacement tube...been there.

Mark D'Agostino
http://www.synergeticproductions.com


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Dan Asselin
Re: Greenish tint.
on Jun 17, 2009 at 3:38:37 pm

I guess the old rule "never assume" always app;ies.

Thanks again

Dan



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