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Old January 10th, 2009, 02:28 PM   #1
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Fluorescent color temperature mix

Hi,

I purchased a 6x 55w fluorescent light system a month ago but one of the fluo was cracked on arrival. I got it replaced and they shipped me a KinoFlo claiming it to be the same color temperature as the one included with the unit.

I put it in, turn the unit on and left it on for now 24 hours... I took a picture you can see here: http://www.microbois.com/temp/DSC_3298.jpg

We can clearly distinguish the replacement fluorescent is bluer that the other fives.

Now the big question, if they're all within 5000K~5400K, should I worry about white balancing properly? What you guys do when one fluo dies or breaks? Do you replace them all at the same time?

Thanks,

Benoit
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Old January 10th, 2009, 02:53 PM   #2
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Hi Benoit.............

First things first:

Well, you won't simply be able to "dial it in" till you figure out what the overall temp is with the "odd" tube, tho' if that's not your one and only light, dialling it in probably isn't gonna happen anyway.

Second, that tube is way outside the normal range for manufacturing tolerances to be the cause.

It quite simply is not the same phosphor as the others.

If it's printed colour code matches the others, then there is something very wrong.

My guess is it's simply the wrong type tube.

Re - check that all the tube makes and codes are identical.

If they are the same, all I can suggest is to check out other manufacturers sites for the appropriate tube type and replace the lot when this set have expired.


CS
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Old January 10th, 2009, 05:00 PM   #3
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Hi Chris,

Thanks for helping me sort this out. I should have been a little more specific in my first post. The six original 55w fluorescent that came with the light system are of a generic brand. Aside from being labeled as 5200K and Ra90 (which I presume is the CRI value), I don't have much more info on them. The fluorescent that has been sent to me as a replacement is the real deal: "Kino Flo True Match Compact Lamp - 55W/5500K". So I can confirm I have a brand mismatch here.

I'm just wondering in the case the various fluorescent are within a few 100K, if it can be a big problem. What do you guys do when you break a fluo or if one stops working? Are you replacing them all at the same time so you get the same batch, same age, etc? What's the usual procedure for such situation?

Thanks,

Benoit
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Old January 10th, 2009, 09:02 PM   #4
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Hi again........

Been doing a tad research.

Found this little snippet on Wikipedia:

Quote:

"Kino Flo tubes, which contained a number of special phosphors designed to eliminate the characteristic tints in the magenta-green spectrum which are present in most domestic fluorescent lights."

Hmm, think you may want to ditch the rest of those generics and put in the real deal.

http://en.wikipedia.org/wiki/Kino_Flo

http://en.wikipedia.org/wiki/Fluorescent_lamp


CS

Last edited by Chris Soucy; January 10th, 2009 at 09:23 PM. Reason: +
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Old January 10th, 2009, 11:22 PM   #5
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The Kelvin measurement really only relates to the red/blue colour shift not the green/ magenta. Lights with the same degree Kelvin reading can still differ wildly - your generic brand ones are very green.

Having said that - how far away from the subject are you using this light ? The light from all of your tubes will mix together to produce a single colour over a very short distance.
If you are shooting video and white balance under this light it wont be a major problem. The issue will be when you want to use other lights that are a different colour to this one.

Yes it would be better to relamp using all Kino tubes - it just costs (like everything in this game)
I often mix tubes in my lights to achieve different looks but it does take a bit of time to work out what colour does what.
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