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green spike w/ tungsten lights


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#1 Daniel Madsen

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Posted 23 February 2007 - 02:58 PM

Has anyone ever witnessed tungsten balanced lights with a greenish hue. I was shooting with a HVX200 using an omni light when I noticed the problem.
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#2 Jonathan Bowerbank

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Posted 23 February 2007 - 03:05 PM

Has anyone ever witnessed tungsten balanced lights with a greenish hue. I was shooting with a HVX200 using an omni light when I noticed the problem.


You saw it through the camera while shooting or in playback? It could be a problem with the camera's white balance...or could you see a greenish hue with your naked eye?

I didn't think it was possible for a tungsten light to spike green, unless it was fluorescent. Interesting.
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#3 Juan Guajardo

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Posted 23 February 2007 - 03:22 PM

maybe was the level of the Chroma Phase
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#4 Frank Barrera

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Posted 23 February 2007 - 10:55 PM

Has anyone ever witnessed tungsten balanced lights with a greenish hue. I was shooting with a HVX200 using an omni light when I noticed the problem.

The most likely cause of this would be a mis-calibrated monitor. The second most likely cause would be either improper white balance or a setting in the scene file. I am not a physicist but from what I understand incandescent objects glow in the red wavelenths and the yellow and partially in the blue. And never in combination. But it never can emit any green wavelengths. The only way to get green out of a tungsten unit is to (obviously) add a green gel or (not so obviously) using CTB to correct to daylight.
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#5 David Mullen ASC

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Posted 24 February 2007 - 02:06 AM

I am not a physicist but from what I understand incandescent objects glow in the red wavelenths and the yellow and partially in the blue. And never in combination. But it never can emit any green wavelengths. The only way to get green out of a tungsten unit is to (obviously) add a green gel or (not so obviously) using CTB to correct to daylight.


Of course tungsten lamps have a green component -- otherwise gelling them green wouldn't do anything to make the light greener. Remember that gels only subtract other color wavelengths, they don't add color actually.

Tungstens are full spectrum sources, predominately though at the red end of the spectrum. However, they don't have a green spike like a flourescent can have (which can also have missing wavelengths as well).
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#6 Michael Nash

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Posted 24 February 2007 - 02:25 AM

Tungsten filaments can behave aberrantly sometimes. I once "snooted" a household bulb with aluminum foil, and the heat buildup caused it to go brilliant green-white. After I took the foil off, the bulb returned to normal color.
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#7 Frank Barrera

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Posted 24 February 2007 - 07:25 AM

Of course tungsten lamps have a green component -- otherwise gelling them green wouldn't do anything to make the light greene

After I took the foil off, the bulb returned to normal color.

my point is that with out adding a gel or some foil or something else you will not see the green. on it's own an incandescent is not going to emit a green spike.
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#8 Jonathan Bowerbank

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Posted 24 February 2007 - 12:14 PM

On a recent shoot I did, I color metered a practical photoflood that showed up with a little green in it...I was surprised.

So it is possible, never seen it with halogen lamps though.
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#9 Walter Graff

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Posted 24 February 2007 - 12:37 PM

The odds of you having a tungsten light that gave off a green tinge would be slim to none since such lights primarily emit light above 500 nanometers. About the only way I have seen such lights giving off strangish colors is when the filament collapses on itself yet remains intact and creates a weird glow which doesn't last long as eventually the added current blows the lamp. Odds are good that your camera or monitoring source was improperly set.

Edited by Walter Graff, 24 February 2007 - 12:38 PM.

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