My cameras can't cope with the supersaturated colours produced by LED parcans. Any hints?

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Mark M
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I've shot two shows recently which have been lit with LED parcans. One was theatre, one dance, but both resulted in oversaturated colours such that my cameras - Sony EX1s, and Sony Z5Es recording to Ninjas - just couldn't cope with the bright blues, and I've ended up with something very ugly indeed. Even lots of post-correction couldn't fix it.

I've never seen this with old-style tungsten Parcans, but all the theatre techs tell me that LED is the way forward for Parcans: cheap, cool, long lasting, robust, low power consumption, and infinitely variable in colour. So I need to learn how to shoot under these conditions!

Any survival hints?

Cheers

Mark

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DAVE M
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Re: My cameras can't cope with the supersaturated colours ...
no survival tips but I do a regular gig at the Brighton Dome and this summer they'd shifted to an LED Par wash for the pre show and interim bits and bobs.
 
It drove my Z7 camera nuts. I do a live mix so it's hard to fix and TBH I didn't bother but eventually the LX crew tweaked it and added some tungsten to the wash which helped.
 
It looked ok to the eye but horrible to the camera. There was red carpet that had a terrible hue to it.
paulears
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Re: My cameras can't cope with the supersaturated colours ...
It's not the LEDs really, it's the fact that for ever, lighting designers have wanted saturated colour - BUT - it was so wasteful of light. Music LDs love Lee 181, Congo Blue - but you need a large amount of it. Same with the reds, Lee 106 primary red is popular, but again, you need a lot of it! Many people with less equipment, or larger stages have chosen flame, or some of the medium/dark blues as they have a better transmission figure. With LED, you can now have just blue - no red or green components and washing a stage in this looks amazing to the eye, but it messes with the agc, if you use auto, and I've discovered that the decision to NOT use auto settings is even more important. If you look at a vectorscope of the images that look wrong, I think you'll see that you've over exposed for the 'average' level, squashing the colour, which looks unpleasant. The zebra pattern on my own JVCs doesn't seem to be quite right on saturated red or blue, but better on green? No idea why. Don't forget that LED doesn't really 'have' a proper colour temperature, because it's three monochromatic colours that blend to give an impression of white. Full R,G & B on an LED fixture does not mix to give white - it gives a dirty white kind of colour, quite unlike real white. The very latest theatrical LEDs have RGB Plus a white matrix - which helps no end.
 
When programming, the almost standard way of working for the theatrical people is to select just red, or blue, and then warm it up if it isn't right - but very often, I dial up full blue, love it and leave it. Same with red. I would resist all attempts to get me to change this unless the video people were at the programming session - which they never (or rarely) are. Once it's approved by the director, and plotted - changes are resisted because to the designer, his eyes say it looks great, and that is what he's paid for. If he adjusts it to suit the camera, to him, it looks worse. My own rule is that if I'm designing for the video, then I expect a video feed to a monitor from the video people - and then I design to the screen. Normally, I design to the audience, not the camera. If you've ever been to a Britain's Got talent, X-Factor, Strictly or Dancing on Ice, the lighting to the eye looks very weird, to the camera, great. Very rarely can you ever do both - one always suffers, and it's up to the producer/director to decide which gets priority.
infocus2
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Re: My cameras can't cope with the supersaturated colours ...
I think paulears is getting close with comments about the problem not being the LEDS themselves or the cameras - rather that we (and cameras) aren't used to saturated colours.
 
I suspect that what is happening is basically overexposure. From memory, the luminance signal is derived from R,G,B according to the following formula - Y=0.3R+0.69G+0.11B. Consequently, if only the B channel is giving an output, even when the camera is exposed to be near clipping on the B channel, the luminance level will only be about 10%. Hence zebras will be useless as an exposure guide, and same for any form of autoexposure - they rely on high luminance levels. The only decent guide is likely to be an R,G,B histogram - expose to get to 100% on the highest colour channel.
 
This also shows why "The zebra pattern on my own JVCs doesn't seem to be quite right on saturated red or blue, but better on green? No idea why." Even if it did only excite the camera green channel, then 100% green would still give a fairly respectable 69% for luminance. In practice, almost any saturated green light is likely to give some response in the red or blue channel as well, due to the spectral responses of the camera channels.
 
And I agree with the conclusion - you have to make a decision to light for the audience OR the camera. And if the latter, then yes, light looking at the image on a quality monitor and forget what your eyes tell you looking at the scene directly.
 
If that's not an option, then just be careful with the exposure, err towards the low side, and try to make use of a colour monitor or colour histogram if you have it. Don't let any of the channels clip.
paulears
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Re: My cameras can't cope with the supersaturated colours ...
I'm glad there's some physics to back up my practical theory. The blue channel spec does seem to be tweaked for the old days where you just couldn't get huge amounts of blue into a space. Up until I invested in new LED kit, I'd light a stage with perhaps 6 or 8 2K Fresnels but any of the dark blues were hugely inefficient, and they'd also burn out regularly. Now I can do blue to the degree that was impossible before. If a camera looks at it, with the luminance info above, no wonder the images look a bit odd.
 
The only real snag I can see to adjusting this from the lighting designer viewpoint is that to make it more camera friendly, I either have to introduce green or blue, or possibly white. Doing so wrecks what I'm trying to achieve. It's common now for the costume designers top choose fabric colours that work in these lights, and adding other colours changes the look of the colour. It's also common to also make use of the Samoiloff effect, where you use patterns in white and say, blue, that when lit with blue light vanish, but when lit by red light appear as a vivid red against black. This can't be 'coloured up'. It's a common trick in dance shows - where you can kind of change costume, mid piece. The only real solution is greater camera control and a good monitor, I guess - IF - you need to record this kind of thing.