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The Color Temperature of these Lights


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#1 Tim Carroll

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Posted 19 November 2009 - 09:33 AM

Trying to shoot the scene below, but in color. The lights look to be those newer style, I'm not sure if those are sodium vapor or "halogen" or what they are, so I'm a little unsure of the color.

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Want to shoot the scene on 5219. Is it best just to shoot a gray card at the beginning and then let the colorist try to fix the light color? Should I throw an 85 in front of the lens?

Any and all information would be greatly appreciated.

Thanks,
-Tim
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#2 Adrian Sierkowski

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Posted 19 November 2009 - 09:52 AM

Grey card and time it out. Chances are those lights'll read cyanish. I shot some footage under similar lights but I haven't got it 'round but I'll see if i can get a frame grab from it.
I'd not throw a filter in front of the lens so as to preserve stop as best one can. I kind of like how cyan the lights read, though I'd recommend something "white" as a key, but that's just me.
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#3 David Mullen ASC

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Posted 19 November 2009 - 11:11 AM

Why didn't you take a color photo of the location -- that would answer your question pretty fast as to what the colors of the different sources are, though you should be able to tell a tungsten, sodium, and metal halide / mercury vapor source with your eyes.
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#4 Tim Carroll

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Posted 19 November 2009 - 12:20 PM

Why didn't you take a color photo of the location -- that would answer your question pretty fast as to what the colors of the different sources are, though you should be able to tell a tungsten, sodium, and metal halide / mercury vapor source with your eyes.


That's a small crop from a medium format shot taken a while ago, for something totally unrelated. Just happens to be the same street and intersection.

They are definitely not tungsten, but I do not have enough experience to tell between a "sodium, and metal halide / mercury vapor source". Which is why I asked.

Best,
-Tim
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#5 Adrian Sierkowski

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Posted 19 November 2009 - 12:27 PM

Sodium=Orangish, Mercury is bluish irrc, and the 3rd I forget.
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#6 David Mullen ASC

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Posted 19 November 2009 - 12:48 PM

I do not have enough experience to tell between a "sodium, and metal halide / mercury vapor source". Which is why I asked.


I'm sure you can see the difference between a yellow-orange (sodium) streetlamp and a blue-green (metal halide / mercury vapor) streetlamp -- orange versus blue is a fairly obvious difference. The brighter metal halides, like you see inside gymnasiums or lighting auto dealerships at night, tend to be brighter and thus look "whiter", but it's a cold white that reads as cyan (blue-green) on tungsten-balanced film. But sodium streetlamps always look orange-ish to the eyes even compared to tungsten sources.

I took this snapshot of a lighting set-up from "Assassination of a High School President" -- you see a mercury vapor fixture on the end of the low building which I added, and the one on the streetlamp on the right, but you can see sodium fixtures on the top of the water tank and in the far background. I added an overhead spotlight (tungsten gelled with Cyan 60 to look like mercury vapor) on the actor but white tungsten light hitting the water tower and metal arch/trussle/whatever-that-is:

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#7 Tim Carroll

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Posted 19 November 2009 - 01:12 PM

Thanks for the feedback. The issue I'm having is they are the newer type of streetlamps, and give off a brighter, more whitish, almost halogen type of light. They seem to be on the warm side, but not as orange/warm as tungsten, and definitely not a visible blue green as in your picture David.

My concern was that they may be too "white" for tungsten film, so I was wondering if I should throw a warming filter on the lens. It sounds like, from what you describe David, that they are the bright metal halides which probably will read pretty blue-green on 5219. So it would seem that an 85 might be the right "fix" for the lighting.

Thanks,
-Tim
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#8 David Mullen ASC

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Posted 19 November 2009 - 01:20 PM

My concern was that they may be too "white" for tungsten film, so I was wondering if I should throw a warming filter on the lens. It sounds like, from what you describe David, that they are the bright metal halides which probably will read pretty blue-green on 5219. So it would seem that an 85 might be the right "fix" for the lighting.

Thanks,
-Tim


Generally you need all the exposure you can at night, so there's no point in filtering the lens for a light that is in the 5600K range, you can time that in post (unless you have so much exposure that you can get away with a filter... but at that point, you probably have enough exposure to use a 250D stock!)

Just take a digital camera down there, set it to tungsten-balance, and take a snapshot and see how it looks, color-wise.
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#9 Tim Carroll

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Posted 19 November 2009 - 01:27 PM

Just take a digital camera down there, set it to tungsten-balance, and take a snapshot and see how it looks, color-wise.


Yeah, I think I'll go down there and do that tonight.

Thanks again guys.
-Tim
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#10 Tim Carroll

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Posted 19 November 2009 - 09:23 PM

Just take a digital camera down there, set it to tungsten-balance, and take a snapshot and see how it looks, color-wise.


Okay, I did just that. Set the WB on the camera at 3130º as it did not have a setting for exactly 3200º.

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The lights are coming out white to slightly blue. They don't look as blue-green as the mercury-vapor lights in your shot from Assassination of a High School President but they don't look warm either. It does look close enough that it could be fixed in color timing. What would you say those lights are, metal halide?

Again, thanks for the help,
-Tim
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#11 David Mullen ASC

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Posted 20 November 2009 - 12:09 AM

Yes, they look like fairly modern metal halide lamps, not as greenish as mercury vapor but still close to daylight balance.
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#12 John Sprung

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Posted 20 November 2009 - 02:50 AM

Maybe they're LiFi's -- they look really nice for metal vapor, though recently they've been adding more stuff to improve the color of vapor lamps. You have plenty to work with in timing there.




-- J.S.
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#13 JD Hartman

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Posted 20 November 2009 - 03:09 AM

Maybe they're LiFi's -- they look really nice for metal vapor, though recently they've been adding more stuff to improve the color of vapor lamps. You have plenty to work with in timing there.
-- J.S.


And.....Li Fi, is slang for??
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#14 John Sprung

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Posted 20 November 2009 - 03:32 AM

And.....Li Fi, is slang for??


It's a new lighting technology:

http://www.luxim.com/

So far, they're interested in the large outdoor and architectural markets. High efficiency, good color, but not scalable to small outputs. Something equivalent to a 1K is about the smallest practical unit.



-- J.S.
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#15 Alex Zustra

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Posted 20 November 2009 - 03:32 PM

Could someone explain color timing?
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#16 Adrian Sierkowski

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Posted 20 November 2009 - 05:26 PM

Color correction, also called color timing, is using post tools (either built into an editing program or in a proper color correction suite) to "fix" the colors recorded. and example would be removing the green from a shot under floro tubes...
here's a rough example from something I just did (the flat scan and where I intend to take it in color correction):

the first is before and the 2nd after.


In this case, color correction will be used to add a "look" to the piece (adding yellow and a bit more contrast to taste) as opposed to removing a color cast, which can also be accomplished if you like.

That's it in a nut-shell. there's a bit more, such as making sure your footage looks "the same" across multiple platforms (e.g. film/hd/sd) as each place you "view" an image has a slightly different idea of how things should look (see also, color space).

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#17 John Sprung

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Posted 20 November 2009 - 06:38 PM

There are two aspects to color timing. First is making the look you want, as Adrian described. The other is tweaking the color across cuts within a scene, so they match imperceptably. The first involves big creative color changes, the second is hair by hair tweaks to extend those creative decisions to all the shots in a scene.

It gets the name "Timing" because it consists of a list of color corrections and the times within a reel that they're supposed to be applied. Getting the timing right was the hard part early on. In some old movies if you go thru frame by frame, you can see the lights change a frame or two early or late on some cuts. Of course in the B&W days, it was just plain timing.... ;-)





-- J.S.
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#18 Adrian Sierkowski

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Posted 20 November 2009 - 06:44 PM

Another way I've heard it put by one of my favorite colorists is "fixing DP mistakes." As John mentions and I dumbly forgot, the hair by hair tweaking so that scenes which are often shot far out of order match to seem as though they're all occurring at the same time in the same space, though this is rarely the case.
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