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1/4, 1/2 and full gels

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John Shand
1/4, 1/2 and full gels
on Nov 12, 2011 at 11:33:49 pm

Hi all,

I'm currently looking to get some green minus and plus gels. Three options are coming up 1/4, 1/2 and full. I just wander what situations you would need the 1/4 and 1/2 gels over the full.

Any advice would be much appreciated.

Thanks


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Dennis Size
Re: 1/4, 1/2 and full gels
on Nov 13, 2011 at 1:36:34 am

What are you using FULL Plus and Minus GREEN for? That's a lot of correction!
Simple logic......You can always make FULL from two halves. If you only have FULL -- and it's too much (which is very likely) -- you can't make 1/2 or 1/4 out of it.

DS



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Bill Davis
Re: 1/4, 1/2 and full gels
on Nov 13, 2011 at 3:41:26 am

Concur with what Dennis said.

Also, remember that all filters are essentially SUBTRACTIVE - and generally, the more color in the gel, the more you're lowering the light transmission qualities of it.

So the more correction you add, the more it blocks the full transmission of light.

FWIW.

"Before speaking out ask yourself whether your words are true, whether they are respectful and whether they are needed in our civil discussions."-Justice O'Connor


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John Shand
Re: 1/4, 1/2 and full gels
on Nov 14, 2011 at 9:36:01 am

Thanks for the quick responses.

I am frequently in situations where i need to correct LED Litepanels (daylight) vs fluorescent lighting.

Surely i would want to eliminate all the green from the fluorescent or add full green to the LED lights? Would i get a strange colour balance if i only used 1/4 and half?


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Bill Davis
Re: 1/4, 1/2 and full gels
on Nov 14, 2011 at 5:54:03 pm

John, the "issue" isn't "too much green" as much as it's too little "not green".

Most modern energy efficient light emitters including both LED and fluorescent technologies have "holes" in their visible spectrum output. So to "correct" them, all a filter does is BLOCK more of the spectrum that's remaining. (filters can only FILTER things, not add something that's not already there.)

So ALL gel filtering is subtractive.

In both LED and fluorescent technology, they do their best to add coatings to the tubes or emitters to get as close to "full spectrum" as possible, but each falls short typically. So yes, adding "plus green" or "minus green" (magenta across the color wheel) gels to a light can correct the spectrum of an LED or a fluorescent that has a similar color gap and get it "closer" to another source. The amount you need depends on what the original light is putting out.

Look on the LEE filters web site and study their gel swatches and you'll see that the "color correction" gels are typically labeled with how they raise or lower the color temperature of the light.

Also do a web search on "mired shift" and you can get a lot of info on matching light color temps.

Good luck.

"Before speaking out ask yourself whether your words are true, whether they are respectful and whether they are needed in our civil discussions."-Justice O'Connor


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