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gelling a practical


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#1 Sean Conaty

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Posted 16 February 2008 - 03:49 PM

i want to put a gel on a practical lamp but I want to make sure there isn't any spill. Is there the one, great way to gel the practical? do you wrap the bulb then tape the top and bottom?
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#2 Jonathan Bowerbank

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Posted 16 February 2008 - 04:22 PM

i want to put a gel on a practical lamp but I want to make sure there isn't any spill. Is there the one, great way to gel the practical? do you wrap the bulb then tape the top and bottom?


What's the fixture like? Will the bulb itself be in the shot? And what's your desired effect?
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#3 Sean Conaty

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Posted 16 February 2008 - 04:49 PM

What's the fixture like? Will the bulb itself be in the shot? And what's your desired effect?


the bulb itself won't be in the shot but the lamp will be. i was thinking of putting a higher wattage bulb and dimming it down, but i wanted to be more precise so that i could augment it with a Baby and have a matching color temp.
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#4 David Mullen ASC

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Posted 16 February 2008 - 05:30 PM

It's very hard to gel a practical lamp, other than ND gel a lampshade to make it darker. But to gel the whole lamp to shift the color temp is very hard unless it has fluorescent tubes that can be wrapped in gel. A tungsten bulb gets too hot to gel, plus it's round. Gelling the top, bottom, and sides of a lampshade is very difficult, not to mention that you are trapping all the heat of the bulb so it will probably burn out quickly.

The usual method is the gel any movie lights to match the practical, not the other way around.
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#5 Dan Goulder

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Posted 16 February 2008 - 06:23 PM

The usual method is the gel any movie lights to match the practical, not the other way around.

Do you ever use something like an 82 filter in conjunction with this setup, in order to give a slight boost to the overall color temperature, or just opt to shoot it "warmer"? Thanks.
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#6 Sean Conaty

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Posted 16 February 2008 - 06:39 PM

what i'm trying to do is shoot mixed color temperature so would be shooting at 3200 with daylight coming in but the practicals really warm. so essentially the outdoor light is much bluer than normal and the indoor practicals are much warmer than normal. very similar to deakins' look on "a beautiful mind".

-sean
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#7 Mike Lary

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Posted 16 February 2008 - 09:43 PM

Could you shoot 5600 and put CTB on the windows? If you have enough light coming in the windows to compensate for the drop in light intensity, the baby and practical would be extra warm with probably little if any correction needed to match them.
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#8 David Mullen ASC

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Posted 16 February 2008 - 10:51 PM

Could you shoot 5600 and put CTB on the windows? If you have enough light coming in the windows to compensate for the drop in light intensity, the baby and practical would be extra warm with probably little if any correction needed to match them.


The daylight is already 5500K and the practicals 3200K, or less, so why would you want even more of an extreme difference by adding even more blue to the windows? Already you have enough of a difference for the daylight to read blue-ish and the tungstens to read warm if you just color-corrected for the middle, halfway between them.

If you (Sean) want that difference, why gel the practicals? If you want a little less extreme of a difference, you can use 4800K blue-painted photofloods in the practicals, which will still read slightly warm in daylight (and warmer if you dim them), though it sounds like what you want is the 5500K / 3200K juxtaposition.

If I'm shooting color negative that's balanced for 3200K, I wouldn't bother using a pale blue camera filter to cool off some warm practicals, that's more than within an easily correctable range. The only reason I can think for doing that is if using a digital camera like the RED that is naturally biased towards daylight color temp and gets noisier in 3200K, assuming I have the stop for a blue filter. If I were using 5500K color neg stock in 3200K lighting and wanted to correct a little of it out, I may use a pale blue filter, again, assuming I can afford the light loss.
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#9 Jonathan Bowerbank

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Posted 17 February 2008 - 04:59 AM

oh, by the way, are you shooting film or DV/HD video?

If it's video, you can do a white balance for the daylight with a 1/2 CTB over the lens. That way the daylight will be blue, but not TOO blue, and your practicals will also read rather warm.

You can do the same in film if you're using tungsten stock by shooting a grey card under tungsten light with 1/2 CTB over the lens (1/2 CTB under daylight if you're shooting daylight film)

Edited by Jonathan Bowerbank, 17 February 2008 - 05:02 AM.

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#10 Sean Conaty

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Posted 17 February 2008 - 05:38 AM

The daylight is already 5500K and the practicals 3200K, or less, so why would you want even more of an extreme difference by adding even more blue to the windows? Already you have enough of a difference for the daylight to read blue-ish and the tungstens to read warm if you just color-corrected for the middle, halfway between them.


David, I think this is a great idea.

Shooting on 5212.

But still, if I were to want to warm up the practical even more, what would I do? color correcting halfway will effect the entire image, but i want to just control the tungsten practical without effecting the daylight.
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#11 Stuart Brereton

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Posted 17 February 2008 - 08:10 AM

why not use an over powerful bulb and dim it down? Domestic bulbs are often as low as 2900k anyway, so dimmed they'll read very warm. Then it's simple to gel your movie lights to match
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#12 David Mullen ASC

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Posted 17 February 2008 - 12:04 PM

Yes, dimming down a stronger bulb would work. I mean, if you really want that extreme of a difference, more than 5500K vs 3200K, then the idea of gelling the daylight window blue would also work -- you could use a daylight balance stock, have the tungstens go orange, and gel the windows to look bluer. Seems extreme to me though.
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#13 Andrew Brinkhaus

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Posted 18 February 2008 - 11:59 AM

Like others have said, I would use a higher wattage bulb on a hand dimmer, you could be looking at anywhere around 2600K on that if you wanted. Then Gel your windows with 1/2 CTB to push the blues a little. Then matching your film lights is easy! That is what I would do in your situation, anyways. Best of luck!

Edited by Andrew Brinkhaus, 18 February 2008 - 12:00 PM.

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#14 Sean Conaty

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Posted 27 February 2008 - 02:48 AM

so i charted with a 1/2 CTB and was relatively happy. i feel like the blue is too blue and the orange not enough, which is great because i'll be able to warm it up in the timing and get exactly what i'm looking for.

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#15 Chayse Irvin

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Posted 28 February 2008 - 05:58 PM

Robert Elswit did a similar thing in Magnolia creating a separation of color by sending light through a blue bedsheet from out side and then putting 1/4 to 1/2 CTO on the practical lamps.

http://www.chayseirv...warmandcold.mov
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