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Old May 3rd, 2004, 10:40 AM   #1
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Two gel/color temp/wattage output questions

Hi all. Two things I'm needing to do:

1) Will have a 750 watt Tota in a med Silverdome aimed at a speaker, and a row of (6) clamp on work lights (200 watts) spaced about 5 - 6 feet apart, clamped on wooden support beams (on an approx. standard 8' old beam ceiling/roof) shining down on the audience. But if the color temp of the Tota is going to be 3200, while the color temp of the 200 watt softlights (in the row of clamp lights) is 2800, there isn't really a good way to correct the difference in this instance, is there? Am thinking it'd just be easier to color correct in Vegas later.

2) When lighting a stage in front of a campfire (stage is about 2 1/2 feet off the ground), I'm thinking of pointing two Omni's up from either side (about 18 inches off the ground), with orange gels on them, to hopefully blend in with the flames. But my concern is how much the gel reduces the Omni's 500 watt output. Is there a chart that tells how much wattage I lose using a full/half/quarter CTO gel? And for anybody who has lit up a campfire, what strength gel did you use (or would anybody rec.)?
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Old May 3rd, 2004, 08:23 PM   #2
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If you were to do a manual white balance in an area where you had the effect of both color temps you may be able to set the camera to a color temp somewhere between the two.

In such a rustic environment, would the added warmth be all that bad. You could, as you say change the color temp in post.

So far as the campfire, I'd manually balance and enjoy the added warmth of the fire.
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Old May 3rd, 2004, 08:43 PM   #3
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I think "orange" will be pretty extreme, unless you're trying to create an exaggerated effect. I've used an un-gelled flashlight as fill next to a campfire and it looked pretty good. Based on that, I'd say to try (roscolux) R08, R09 or maybe R18 at the most.

Regarding light output, if you look in the Rosco swatch book you will see transmission curves for each gel. This info is also available online. Click on the little chart next to the color swatch. Note the "TRANS" number. In the case of R08 it is 86% which means that (overall) 86% of the tungsten light will pass through the gel. The graph shows tranmission vs wavelength.

Note that the color swatches on this web page will give you a ballpark idea of the actual gel colors, but they really are not very accurate.
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Old May 3rd, 2004, 09:13 PM   #4
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Bryan, Boyd, all VERY helpful. Will pick up a couple of the gels you mention Boyd, if I don't have anything similar. Have to check. (I have some Lee filters... some are close to Rosco #'s, and others are not.) Will give them a try lighting my friend's backyard fire pit.

Thanks for taking the time to respond. Just the kind of info I was hoping for. :-)
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Old May 3rd, 2004, 09:31 PM   #5
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Happy to help. If you go to Lee's website you should find similar data on transmission for their gels. I agree that the best approach is just to do some experiments and see what looks good. My background is theatrical lighting, and I have a lot to learn about video. However, I'd suggest trying a different color on the two lights. Contrasting colors from different angles help define three dimensional shapes. You might even experiment with a blue gel on one of the lights from a higher angle to simulate moonlight or night sky light, then use the warm gel as a firelight "key".

Happy shooting!
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Old May 4th, 2004, 12:28 AM   #6
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Marcia
I remember you mentioning that you wanted to keep it simple.
I envision a rustic setup, am I wrong? A little warmth can be very mood enhancing.

To be honest I can't really say that I've seen 2800k vs 3200K. It may be worth and experiment. Set the camera for 3200 and see what effect the 2800 gives you. Try a manual white balance and see what that gives you.
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Old May 4th, 2004, 01:00 AM   #7
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Bryan, "rustic" makes me smile. Yes it is, very. The doc is set at a camp for kids with a life threatening disease and it's a mile and a half from civilization. I'll be living among the bears, in a tent, for a little over six weeks. There are limited outlets, but in the scenarios discussed, there is enough for some illumination. It won't exactly be a Hollywood shoot, but hopefully what I've planned will do the job. (I questioned a seasoned feature film gaffer at one point, about one of my "settings," and he suggested a 4,000 watt generator and 4 Molepars to light the dining hall. Well, the main thing I want to get is the food line which shows their food choices and why, and two Totas should light that part of it up just fine. The rest of the dining room will be strategically out of the picture. I don't have the budget to rent 4 Molepars and a generator for six weeks, just to get a wider shot. Hey, you do what you can on the budget you've got, ya know?)

I have a few weeks yet, enough to finalize what I'm taking and run tests regarding the questions I posted here. I'm sure it'll work out. Unfortately I have to sleep, or I'd get a whole lot more done. ;-)

Know that I appreciate all the feedback all of you and others have so graciously offered... more than you'll ever know. Many thanks for your interest. Be warned, I'm quite certain more things will occur to me before I leave!

Marcia
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Old May 5th, 2004, 12:11 PM   #8
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Marcia, I know you have more urgent things on your mind, but you mentioned having a Tota/Silverdome combo. So do I, but I have yet to put it together. I have the VC-L4001 adapter--did you have any real difficulty with it? Is it easy to adjust with the Tota? Maybe I'm thinking it looks more complicated than what it is.

Anyway, good luck with your project!
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Old May 6th, 2004, 12:45 AM   #9
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Bryan, IMO the Photoflex/Tota adapter for the Photoflex Silverdome which I bought through B & H (not sure if it's the same model # you mention... just got home and would have to go dig out the info... will do that tomorrow if you need... let me know) is a ridiculous contraption. Assembled together they make a beautiful light, but come on... surely they could've come up with something a little more elegant. FYI, I noticed that the adapter I have is "discontinued," so just maybe they've come up with a better alternative of late. Dunno though. In any event, if you have the same gizmo I do, it does indeed work, but just be sure that the stud on the adapter (mine is goldish whereas the rest of the thing is silver) is FIRMLY screwed on (I had my husband who is strong as an ox give it a few twists after I'd done what I could), otherwise the Tota slips on it, and doesn't stay straight. The prong things fit in as they should, but again, it takes a bit of fiddling. When assembled the medium Silverdome is a bit large to haul around, but for the interview shoots I'll be needing it for I'll most likely assemble it in the motel the morning of the shoot and haul it through the medical center (for ex.) intact on my cart. One less squirrely thing to worry about on site.

In hindsight, were money not an issue (yeah, right!) I'd go with the Starlight inside it or the Lowel Rifa version of the same. But on the budget I'm working with, using the Tota inside Photoflex (the Tota then being available for other functions w/o the Silverdome) was/is a more econimical way to go. It's kinda like the homemade cookies ( approx. $3.00 ea.) I'm using cut from foam board from the craft shop... and the frosted shower curtain ($3.99 at K Mart) in lieu of a $400+ Scrim Jim. Let's just say George Lucas doesn't use my tools on his shoots! ;-) But I'm doing what I can to emulate as professional a shoot as I can. And as I said, the Photoflex with a Tota inside may be less than an elegant and easy solution, but it really is a beautiful light/effect.

It will be a long time before I know if I've succeeded with my intent. That's the trouble with having tasted what Hollywood has to offer and then trying to do it yourself... a whole different ballgame. But I believe in this story. I may be nuts (yeah, ok, I definitely am) but only a crazy person would try. Nobody else would risk it on this budget. Then again, I have a rock on my desk that I bought (that says volumes in itself!) that someone carved "risk" into. (sigh) So, funky tools or not, I'm going for it.

Too much wine after a long day... hope somehow this was a help. Need sleep.

Night,
Marcia
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Old May 6th, 2004, 08:06 AM   #10
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Thanks for the info--I queried Photoflex about the adaptor (the truth is, I lost the instructions. What a pro!) They sent me downloaded instructions--for the Lowel DP. Close, but not close enough. I replied, and hope further info is imminent. I agree the adaptor contraption is a study in "what is it?" That's why I was curious on your take.

If anyone deserves a fat PBS grant for your endeavor, you do!
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