White balance debate

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Nintembo
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Joined: Jun 22 2004

I was having a discussion with a friend in regards to white balancing and I was interested in a few extra opinions.

Is it ESSENTIAL to do a new white balance everytime the camera is put in a new position.

I.E.

A shoot within a bedroom. The actors are under say two red heads. I am filming 'Sunject A' for the 1st time so I set up a white ballance. I now record 'Subject A' from a new position - do I create a new white ballane?

Thoughts?

Alan Roberts
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Joined: May 3 1999

No, it is not ESSENTIAL do rebalance in new conditions. It may be a GOOD IDEA in some circumstances, but that does not make it ESSENTIAL.

If you are in control of the lighting, and your production will have a colour grade, then all you need to do is to use the appropriate filter and/or setting for each new lighting condition. So, if you're indoors using tungsten you use a 3,000K setting and/or filter combination, if outdoors you use a 5,000-6,500K setting and/or filter combination, and if you're in mixed lighting you use a 4,300K setting and/or filter combination. That's what professionals do on professional productions, they get paid to produce good pictures, I get paid to advise them on how best to do it, you see the results on tv and in the cinema.

If you always rebalance, then you run the risk of losing the subtle nuances of lighting effect. You can create many effects using lighting, if you always rebalance to the mean lighting, you lose much of that and throw away the whole point of using lighting for effect in the first place. Also, if you use presets and filters, your colourist will always know that what he sees is what you saw, so he won't be tempted to try to undo lighting oddities because he'll know that they were deliberate.

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infocus
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Joined: Jul 18 2003

I'll agree with everything Alan says, though I doubt if most people refering to these forums are likely to have access to full blown grading facilities. Equally, DV/HDV has less room for such adjustments than Digibeta/HDCAM (8bit v 10 bit recording, colour space etc), so it's more important to get it close at time of filming.

And yes about the nuances of lighting. Would you balance for say, a candlelit scene? It may make it technically correct, but would lose that warm glow that makes it look, well, candlelit! Normally better to go tungsten preset, and let it go warm.

Most important is to avoid mixed lighting in general - unless you're after an effect and are pretty confident of what you're doing. Classic example would be a daylit classroom or office, with a wall of windows and with all the fluorescents on. You won't win there however you white balance - and the best bet is to turn the fluorescents off and confine shooting to one general favoured direction, away from the window, unless you've got lots of light. Or wait until the sun goes down, and shoot all fluorescent. Generally, most fluorescents tend to be warm, and balance reasonably well with tungsten, but it may be worth doing an ambient colour balance, seeing what value you get, and lighting to match. And don't trust the LCD screen on such as an FX1 for more than ball park "is it OK?" - that goes for exposure too.

tom hardwick
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Joined: Apr 8 1999

If you have left such things to the automation, a good NLE system will allow you to vary the colour correction over time using key frames, but this is not always a good solution. Many editing cards also have a 'white balance' colour corrector. This is marvellous for aligning two different cameras colour wise. One click on the white table cloth in frames from both films and its done. There will also be other problems in using the camera’s WB presets, as people under the shade of a tree for instance will look a lot bluer than they should and gentle shifts occur simply when the sun goes behind a cloud. Problems also occur when daylight filters into a room that’s lit by a mix and mess of strip and incandescent light. In these instances you really have to decide what’s important, always remembering that in post it’s a lot easier and more successful to warm up an image than it is to cool it down. If in doubt, set the camera to the artificial light setting.

A shot of the house in the evening may mean that sodium street lights are all you have to work with. You try all the preset settings and realise that none are correct. You don’t have a white card to do a manual white balance so what to do? Well, here’s a neat trick. Put your camera on maximum wide-angle so as to take in as much building and garden as possible. Now select the ‘see-saw’ manual white balance setting and activate it (usually by pushing in the little wheel). Wait a moment and let the camera decide what it thinks is right. This has saved me many a time and is a remarkable demonstration as to the very wide colour balance limits programmed into your camcorder. In a nutshell: Don’t know what setting to choose? Choose wide-angle and simply manually white balance on whatever’s in the viewfinder.

tom.