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How to remove yellow cast on dark video made brighter?

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Jaanus Henno
How to remove yellow cast on dark video made brighter?
on Nov 27, 2014 at 1:29:54 pm

Hi!

I have some footage of a person speaking, shot in quite a dark room. So after adding all the exposure etc. effects to make it better, there is still a yellow cast (I mean yellow particles flowing around) on the whole screen. It can be removed, to some extent, with Neat video and Sony's chroma blur, but still some remains and I'm not satisfied. Especially it can be seen on the shadows and if the shadow or dark side is on the face, it looks too yellow.

What are the techinques to remove the yellow cast?


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Bob Peterson
Re: How to remove yellow cast on dark video made brighter?
on Nov 27, 2014 at 6:44:23 pm

A yellow caste can be removed using a color curve. You can reduce the color for the two colors that make yellow (red and green), or you can increase its complementary color (blue). You will need to figure out where your yellow color lies on the tonal range of the color curve for best results.

However, your description sounds like you may be seeing noise rather than a color caste. If it is noise, the color curve probably will not remove it.


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Graham Bernard
Re: How to remove yellow cast on dark video made brighter?
on Nov 27, 2014 at 6:59:10 pm

Post a STIILL here?

1] I check with LEVELS first

2] One of my WB FXs

3] Then, NEAT video.

G

Video Content Creator and Potter
PC 7 64-bit 16gb * Intel® Core™i7-2600k Quad Core 3.40GHz * 2GB NVIDIA GEFORCE GTX 560 Ti
Cameras: Canon XF300 + PowerShot SX50HS Bridge


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Russ Froze
Re: How to remove yellow cast on dark video made brighter?
on Nov 29, 2014 at 3:56:31 am

Perhaps White balance. Was that done before shooting the footage? If not, there is a good chance that is the cause for the yellow cast. Try the white balance plug.
Russ Froze


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Jaanus Henno
Re: How to remove yellow cast on dark video made brighter?
on Nov 29, 2014 at 4:21:21 am
Last Edited By Jaanus Henno on Nov 29, 2014 at 4:23:24 am

Ok, I tried to change color curve, but as you said this is most likely noise. Actually it is not really noise either, more likely some disbalanced colors or something, an artifact of a low light camera shot or something. Whatever is the situation, Neat cannot remove it completely either. Actually the still image doesn't represent the results quite accurately since when pictures are in motion, the artifacts are less visible. After adding all the effects (WB, Exposure, Neat, BCC Noise Reduction, sharpen) it's pretty good, but still some yellow-green colors flowing all over the screen, especially on darker areas.

I will add a short original videoclip.

And this also brings up another question. When brightening such an image, the color of the face looks too brown, the tone is not proper. But I cannot just change it directly also, that puts other colors out of the balance. Is there anything to do to get the face tone look normal?

https://reels.creativecow.net/film/sample-file


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Graham Bernard
Re: How to remove yellow cast on dark video made brighter?
on Nov 29, 2014 at 11:08:21 am

[Jaanus Henno] " Is there anything to do to get the face tone look normal?"
Jaanus, IMO, you have a fundamental problem - not enough BLUE pixels within the Gamut to get your YELLOW gone when made brighter overall.

I used SONY Channel Blend to ascertain just where and and how many of the RGB Channels were delivering. Here's my results.

Plain Default CB:-


Distributed RED Channel:-


RED, evenly sized and nicely spaced Pixels.

Distributed GREEN Channel:-


Better than the RED, evenly sized and spaced Pixels with no excessive clumping of pixels.


Distributed BLUE Channel:-


But whoaaa, the BLUE Channel shows massive break up and poor pixel spread. Nothing I could do to balance this, by swapping/blending pixels from the other channels, the BLUE channel has, IMHO, gone mostly AWOL to provide that necessary substitution/blend to ultimately loose the YELLOW.

Grazie

Video Content Creator and Potter
PC 7 64-bit 16gb * Intel® Core™i7-2600k Quad Core 3.40GHz * 2GB NVIDIA GEFORCE GTX 560 Ti
Cameras: Canon XF300 + PowerShot SX50HS Bridge


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Jaanus Henno
Re: How to remove yellow cast on dark video made brighter?
on Nov 29, 2014 at 2:10:22 pm
Last Edited By Jaanus Henno on Nov 29, 2014 at 2:10:57 pm

Ok. I checked into the use of Color Blend and it's a little over my head, but I got your point though. I dream that one day there will be someone who will make in depth tutorials of all the effects of Sony Vegas, with practical examples of real life use. Anyway, I learn what I need as I go.

Overall, by throwing in all kinds of stuff, I got it look good enough for myself and my friends, so it's ok. Couldn't get rid of the yellow though:) No problem.

I'm sure there will be a time when all the things we would like to achieve in digital media will actually be possible. If you can just make the computer read your thoughts and act accordingly... But the fact that you can imagine how something should look like means that there is also a way to do it. It's just that our subtle mind processes stuff a lot better than we can actually put into practice through gross hard and software.

And thanks for helping!


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Graham Bernard
Re: How to remove yellow cast on dark video made brighter?
on Nov 29, 2014 at 2:22:53 pm

[Jaanus Henno] " It's just that our subtle mind processes stuff a lot better than we can actually put into practice through gross hard and software."
Got that right, buster! - Our senses are truly amazing.

Glad to be of help - sometimes "good enough" is what's required. BTW, hadn't you posted one of these chaps 3 years ago?

Toodles

Grazie

Video Content Creator and Potter
PC 7 64-bit 16gb * Intel® Core™i7-2600k Quad Core 3.40GHz * 2GB NVIDIA GEFORCE GTX 560 Ti
Cameras: Canon XF300 + PowerShot SX50HS Bridge


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Jaanus Henno
Re: How to remove yellow cast on dark video made brighter?
on Nov 29, 2014 at 2:56:33 pm

The post 3 years ago was a little different matter. That indeed was an overall yellow problem. I didn't know anything about White Balance back then which could fix that issue in a second.

But a bad camera and bad light brings in an array of problems, and some are only to be noticed after getting rid of the worst ones, which at that time was a victory already.

And I go really slow, haven't learned a lot after 3 years...


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Russ Froze
Re: How to remove yellow cast on dark video made brighter?
on Nov 29, 2014 at 5:09:23 pm
Last Edited By Russ Froze on Nov 30, 2014 at 3:04:56 am

Have you tried the secondary color corrector? A color range can be chosen and then modified. This might be of use for the flesh tone problem.
Russ Froze


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