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Old October 24th, 2007, 12:02 PM   #1
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Osram DULUX L are very pink, how to CTO?

Hi,

Recently I've been shooting a lot in a room with some very pink flouro studio lights that require me to manual white balance every single time I shoot or get a pink cast.

What would I use to gel them to the color of halogen lights so I can just use the studio camera's indoor preset? Can just I put a similar gel in front of the camera lens to get the same effect? (the studio camera's lens is not shaped to accept filters)

The lights are a pair of arri studio cool 2's with 2 fluro bulbs each that read "Osram DULUX L 55W 930"

The product page for these bulbs at

http://www.osram.com/osram_com/Profe...X_L/index.html

mentions that these bulbs come in different colors but don't say how to tell which bulbs you have.

While I will if needed, I'd prefer not to have to pull the bulbs to read the back of them or call the vendor who sold them and have them look up the bulbs' color temp.

Thanks,

Shayne Weyker
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Old October 24th, 2007, 07:11 PM   #2
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This is an odd situation in that fluorescents are normally too green. Your pink is probably magenta - the opposite of green. You might try a 1/8 green to see if the problem is diminished. You probably should manually white balance anyway.
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Old October 24th, 2007, 10:26 PM   #3
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The 930 is rated at 3000K
The 940 is rated at 4000K
The 954 is rated at 5400K
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Old October 25th, 2007, 11:41 AM   #4
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Thanks,

OK now if my bulbs are 3,000K temp what would be the right gel to use to make them the color of incandescent lights?

Shayne Weyker
http://weykervideo.com
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Old October 25th, 2007, 06:16 PM   #5
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Incandescents are 2700-3200Kelvin and only you can judge what yours are in that location. If they look more amber than your fluorescents, you might add 1/8 CTO to the fluorescents to get a match. Honestly, if the fluorescents are 3000Kelvin you should already have a decent match unless your incandescents are dimmed. Dimmed incandescents go to a lower Kelvin rating so it would take stronger CTO to match the more amber dimmed lights.

If your fluorescents truly look pink, the color temperature is not your problem. The other color shift was explained to be the "mired shift" and that is the quantity of green in the light. Less green than pure white will give a magenta color that looks pink when it is not severe. A strong magenta is purple, but it look pinkish if it is subtle.
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Old October 26th, 2007, 09:38 AM   #6
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I've seen these particular bulbs quite often and they could normally be described as very yellow "warm" type color. Pink would be highly unusual and I almost wonder if there is something going on with your ballasts thats creating a dimming effect. I've noted that many of these types of (3000K-3200K range) bulbs can go a bit pink during dimming.
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Old October 26th, 2007, 05:10 PM   #7
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I use the 930 all the time without a problem.
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Old October 26th, 2007, 06:12 PM   #8
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I looked closer at the lights along with a much smaller (12x12"-ish) dimmable overhead flouro used as a hair light I didn't think to mention before.

Get this, the hair light did look pinker than the 930s, and, wait for it, the PINKNESS WENT AWAY when i dimmed up the hair light. Thanks Andrew.

It seems to be a very fine line with that light between giving people racoon-like shadows under their eyes with the overhead light too bright and making them look pink with the light too dim.

I could swear I've looked at those 930 before and thought they were pink.... I guess the the pink cast on tape was just the overhead light being pinker than when the camera was last white balanced making the whole image look pink. I did adjust the dimmer some recently. I'll test some time soon and report back.

Shayne Weyker
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Old October 26th, 2007, 09:46 PM   #9
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Yeah, sounded like the exact effect you see when flos are dimmed. And this is all flos--including Kino Flos. It's just the nature of all discharge tubes to change color temp during the dimming process. Maybe we'll figure something out in the future to alleviate the problem.

In fact, you really can't dim any flo much below 50 to 60% before you start seeing the problem. Those that have to have dimming just live with it. Or, you find other creative solutions to dim like bank selects or added diffusion material. HMI can't be dimmed below 50% if you can even dim using whatever ballast you have. If they could, they'd have a similar problem too as would all discharge type lighting.
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Old October 26th, 2007, 11:35 PM   #10
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I never dim my flo's, but as Richard suggests I will use a layer or two of diffusion depending on how many stops I need to kill.
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Old October 27th, 2007, 08:13 AM   #11
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Dimming also shortens the life of any discharge bulb of any kind from flo to HMI... Something to keep in mind.
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