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Old May 25th, 2004, 11:40 AM   #1
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Matching Fluorescents

All,

I did a search on this but couldn't quite find the answer....

I am going to be shooting a fictional racquetball game. The court is lit by about 30 fluorescents 20 feet up, and the white walls that reflect them. We won't be able to gel or replace those.

For my wide shots I am going to be content with those lights... I have no choice. But I am also going to be shooting close-ups of dives and such, and I want to use additional lighting on those.

My lighting resources are a few JTL softboxes (3200K ?) and a few worklights that a much more yellow (not sure the temp).

How bad for color matching is it going to be if I use the softboxes with no gels to provide highlights and accents? Of course the fluorescents will still provide a huge fill.

I'm sure I can find matching gels somewhere, but the softboxes are much larger than any gels I have.

Am I going to be better off just shooting the whole thing with the existing light?

Any input is appreciated, thanks.
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Old May 25th, 2004, 12:29 PM   #2
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You could always use reflectors and white foamcore for fill on the closeups. That way, you'll keep the color temp consistant, but you'll still have some degree of control over the lighting.
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Old May 25th, 2004, 04:53 PM   #3
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Good solution, Ryan. However, with that type of ambient light you aren't likely to be able to pick up too much of an "air bounce" unless you are able to work the bounce quite close to the subject, and it needs to be a large bounce.

Another possibility worth looking into is to get a couple of fluorescent shop light fixtures that you can clamp on to your light stands; then find out from the maintenance people at the raquetball facility what type of fluorescents (cool white, what brand etc) they are using and load those into the shop lights. Thus you have a nice soft light source that matches for not much money, and you simply white balance out the green cast. Even cheaper is if you ask them if you can borrow a few tubes for the shoot, they should have a stockroom full of them.

Now, it is possible to white balance to your softboxes and let the fluorescents go, depending on the type of tube. If you are lucky the ambient light might just come out a little cooler; not so lucky, you'll have a greenish tint to everything. If you really want to use your softboxes, you'll need to gel them with a particular formula. The best way to determine it is with a color temperature meter, but if you don't have one, there's still hope.

Here's a really convuluted but very inexpensive way to go about it: take your camera, a small tungsten lighting unit and a good color monitor (using a flip-out monitor is OK, but not ideal) over to the location. You'll also need a white card built as follows: I'd recommend taking a 3ft x 2 ft. piece of white board/foamcore and creating a hood over one half of it (the right side, say), sort of like a Hoodman.White balance to the existing fluorescents using the open half. Now aim your lighting instrument from alongside camera into the other half (The reason you are using a hood is to keep the overhead lights off that side of the card). Adjust the intensity of the light so that both sides are approximately the same exposure--the side with the tungsten light should actually be a little hotter so that when you gel it down, it will end up matching the ambient side. The monitor will help you with the matching, or if you camera has zebras you can set them to aid with this also.

Now use a gel swatchbook that containts color correction gels (free, and available through your local lighting rental house; Roscoe's Jungle Book is great because the swatches are larger) and start holding different strengths of CTB (color temperature blue) and Plusgreen in front of the light. Compare the two sides of the card (inside and outside the hood) on the monitor.When the two sides match in color, you're done, that's your filter pak! (Chances are you'll be looking at something like a 1/4 blue and 1/4 plusgreen). Now you can go pick up gel sheets; depending on manufacturer, you can usually get a sheet around 20"x24" for around $5, and you are good to go.

Whew, that was sort of complicated! Hope that made sense.
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Old May 26th, 2004, 08:08 AM   #4
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Charles, Ryan,

Thanks for the help.

Ryan - The shots I am going to get are a bit too wide with the relectors, and I think Charles is right away about the source being too diffuse to do that.

Charless - I like the idea of tuning to the white boxes and hoping the flourescent fill doesn't kill me. With the Matrix and all, I guess a green tint isn't too bad for action shots :). I will test that, and I will look for cheaper flourescent instruments to use also... they would be nice to have around anyway.

The halfscreen matching technique was very interesting... I will try that too. I need to get a bigger selection of full gels to have for this type of thing.
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Old May 26th, 2004, 10:15 AM   #5
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Wow! I'd never thought of doing something like that. Thanks, Charles!
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Old May 26th, 2004, 12:57 PM   #6
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Yeah, I made that technique up for the post, never used something like that but can't see why it wouldn't work. The fun thing about DV Info.net is seeing how everyone comes up with inexpensive ways to skin the cat, which is an interesting challenge. Me, I'd whip out my color temp meter, but I only have that because of the film work I do where you don't have a choice of using monitors to determine the gelling required.
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Old May 27th, 2004, 10:20 AM   #7
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That's what I love about this place, too. It's taught me that you don't necessarily need a lot of money to create a good-looking image. You just need to know how to buck the system a little. Thanks again.
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