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How do I get rid of unwanted colors in this shot?

http://www.youtube.com/watch?v=mX0omz-W_lU

The white lights you see have purple lines around them. It's not as noticeable on youtube but on an HDTV, it makes a huge difference. Can I get rid of the purple lines or is that just an H.264 thing in the Canon T2i, and I best just forget about it? Just so long as audiences won't be too distracted, by locations that have those kinds of lights.
 
I wanted to shoot the lights at 2000 Kelvin, so if gives that blue-ish effect, as you seen on the ground. But as a result I guess the lights have purple lines around them. If I have to keep the purple lines to have blue light, I guess I can just so long as it looks professional or acceptable.
 
If I were you, I'd shoot under a normal WB, say tungsten balance, and then grade later to give it the look you want.

At least that way you can keep skin tones relatively decent without too much work.
 
Okay thanks, I tried, that but that made the whole sky pink and everything pretty much pink. Maybe I just suck at color grading but I added blue later and everything goes pink more. I posted that one before a few months ago, but I was told before though to get the color right in camera, so such things would not happen later.
 
The high contrast parts of the image are going to have that. Mostly if you're iris is all the way open. To avoid it, keep the big lights out of frame (just zoom in a little, or tilt down more). You probably can't close the iris any farther, but dong so would help with that at all, you'd have to boost the ISO to compensate and will add a little grain to the image... which is a decent trade off for my tastes.
 
Okay thanks. So it's an iris thing. Well I will probably have to show the lights in the image, since I want to show that location from a villain's point of view, as he is spying on another character who will be there. If the audience will not be distracted by the purple, I can keep it. But I will also do some tests with closing the iris and see how far I need to close it and how much grain I will get.
 
It's a lens thing... all lenses do it... it's minimized in the middle of the aperture settings... which is why I say the extremes are not as good an image as the middle. f/5.6 tends to be the sweet spot on most lenses. All lenses have a little bit of chromatic abberation (it has to do with how the lenses are prismatically bending the light at the corners of the frame). Expensive lenses are really carefully engineered to minimize this through extremely precise manufacturing practices... cheaper lenses will have more of it.

It happens toward the corners more and shows up around points of strong contrast specifically. Changing the iris will help minimize it... but it's a glass/light/prism/physics thing.
 
The easiest way is to just not have the lights in the shot... or climb the poles and hang fabric around them so the light only casts downward lighting your scene, but nto straight into the camera.

A lot of time is spent on set making sure that there is never a really bright light source directly hitting the lens. Apart lens flares, super high contrast edges do weird things optically -- as you're learning.
 
we've covered the use of sodium lighting in previous threads with you... they only produce a single color of light, trying to balance to them is folly as there is no light at the wavelengths you're trying to present lighting your scene... you're simply pushing the scene from all orange to all green... as if you were tinting a black and white image green.

Absortpion-emission-line-spectra-of-Na.jpg
 
Well I've read on some sights that sodium is 2000 kelvin, but if you turn the kelvin down to 1500 in the camera, then it the sodium lights come out white. So maybe sodium is more like 1500.

But I will just go with that, since I have to make a decision and not be able to have the colors I ideally want.
 
2100K - physics / science fact... and with the lights producing only light at a VERY narrow range of frequencies, you can absolutely shift your camera's interpretations of that 2100K single frequency to any tint - like tinting a black and white image.

It's remapping the single frequency to a different frequency, thereby coloring it. Study the physics of light and reflectance/transmission - it will answer every single question you've been asking about light / camera stuff lately.

http://www.physicsclassroom.com/lab/light/Llabs.cfm
http://www.physicsclassroom.com/Class/light/
http://www.amazon.com/Introduction-Light-Physics-Vision-Color/dp/048642118X
http://www.physicsclassroom.com/Class/light/u12l2d.cfm
http://www.youtube.com/watch?v=AW_jXrIQXEc
http://www.youtube.com/watch?v=TWhGmwUojBE
http://www.youtube.com/watch?v=OYmLH2PnLpA
http://www.youtube.com/watch?v=CuQMRNg7Zkk
http://www.youtube.com/watch?v=EHMH0uQDEOU
 
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