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How to fix blonde hair that turned pink after keying

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Gabrielle Dorr
How to fix blonde hair that turned pink after keying
on Nov 29, 2017 at 6:07:30 pm

Hi Everyone,

I am fairly new to green screens so haven't come across this problem until now. I removed the green background from a video clip using the keyer and the girl's hair turned pink. She has very light blonde hair and fair skin. Her skin looks fine but there is a tint of pink in her hair. I tried using adding a color mask to her hair but when I change the color it changes her face as well. I can't seem to isolate her hair from her face. Any thoughts?

Here are the before and after shots of the clip:





Thanks,

Gabrielle


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Jeff Kirkland
Re: How to fix blonde hair that turned pink after keying
on Nov 29, 2017 at 10:59:33 pm

You can see the source of the issue from the amount of spill on her hair. Avoiding it in the future comes down to better lighting and moving her further away from the green screen.

Fixing what you’ve got, you could dial down the spill removal until the pink goes away or do what you’ve done but add a shape mask to the colour mask to isolate her hair from her face. If she’s moving a lot you’ll either have to track it with something like Track X or do it manually. With enough feathering you don’t need the track to be amazingly accurate, just ball-park, so it shouldn’t take too long - unless it’s a three hour interview or something.

I’d personally do the key, get the editing done, then send the final result to resolve and track a colour mask there to do the final fix of her hair. Just way better tools than in FCPX.

----
Jeff Kirkland | Video Producer & Cinematographer
Hobart, Tasmania | Twitter: @jeffkirkland


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Chris Wright
Re: How to fix blonde hair that turned pink after keying
on Nov 29, 2017 at 11:47:47 pm

I approach keying in stages, not all at once. this should work for most software.
1. I get a good key, in an intermediate step with no spill suppression. I only look at the alpha channel. nothing else matters. often use garbage mattes and multiple keys are required for hair etc.
2. I conform the key into a new composite, not any color transfer, only alpha channel.
3. I color correct any spill suppression after the alpha matte composite
4. I add final secondary color correction and light wrap


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Brett Sherman
Re: How to fix blonde hair that turned pink after keying
on Nov 30, 2017 at 1:43:25 pm

You might have too much spill suppression. Spill suppression essentially shifts the edges from green to pink to avoid the green halo. Too much gives you a pink halo.

--------------------------
Brett Sherman
One Man Band (If it's video related I'll do it!)
I work for an institution that probably does not want to be associated with my babblings here.


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Chris Wright
Re: How to fix blonde hair that turned pink after keying
on Nov 30, 2017 at 7:23:53 pm

excellent point, which I kind of glossed over. sometimes the built in spill suppressors are just really bad color effects. you can often do secondary color correction much better yourself than a '2 way tint effect'


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Mark Suszko
Re: How to fix blonde hair that turned pink after keying
on Dec 1, 2017 at 5:04:49 pm
Last Edited By Mark Suszko on Dec 1, 2017 at 5:05:42 pm

Spill suppression uses a virtual version of the lighting technique we use in real life, that is, to kill spill off a blue screen, you back-light with what they call a "bastard yellow" or amber light, because yellow is across the color wheel from blue. When keying off green screen, the color on the opposite side of the color wheel is magenta. This is why your tint looks "pink": it's a weak magenta tint being used in the spill suppression software.

Don't even start messing with your keyer, until the raw footage is properly adjusted on your scopes for exposure as well as color saturation. A lot of beginners miss this step and wonder why the shot is such a struggle. Good fundamentals here make the keying go much easier, later in the chain. That lets you generate the key, and then you can go on and color-correct the composited output all you want.

When I'm serious about a greenscreen shot, I bring my MacBeth chart or at least a physical color bar chart to the set and shoot samples with it in the frame, in the actual lighting, then in post I color-correct the raw footage until the chart looks right on the scopes, only then do I attempt keying and and after that, keying is usually instant success, no need to make adjustments. Camera-generated bars are not going to be any help with this; you need to have the chart imaged thru the actual lens.

The pink cast is a sign the spill compensation is cranked up too high; try adjusting the other spill-related parameters, or re-sample the green at a spot closer to the hair, to try and fine-tune the range that gets cut out. I often have to get into the manual control interface and mess with the end points on the controls when this happens to me.

You may want to play with doing a separate luma key and adding that as a traveling matte.

Another thing folks forget is that you can invoke multiple instances of a keyer, and mask it to work in just one area.

The Drop Shadow tool defaults to black... but, most don't realize you CAN change it to another color, like chroma green, or anti-green magenta, and even use it as a kind of "wrap" light generator along a keyed edge, with variable opacity and softness. Might want to play with that.

Another way to save a bad key is to deliberately mess with the color balance and saturation, exaggerating it to the point the shot is useless visually, but has enough contrasts for the keyer to make a clean matte. Then build that matte with black/white and port that matte to a separate layer as a "hold-out" matte, restore the source footage to something human-looking, composite everything.

Some time back, I tamed a troublesome green screen shot by first keying it over a solid, saturated blue, essentially making it a blue-screen shot, and losing all the garbage mattes.

I kinda miss using blue screens - I think when the key is iffy on blue, it's a little less obvious.

I predict we're not far off from the day video cameras using light-field technology record the z-depth of every item in a shot, and on that happy day, we can generate clean "chroma" keys just by selecting where in the depth of field range an image segment is supposed to be visible or not. Call it "Z-keying". And I want the royalties on that idea/name. :-)


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Chris Wright
Re: How to fix blonde hair that turned pink after keying
on Dec 1, 2017 at 7:01:51 pm

great post! also, I have kinda done some stuff similar to 'normalize' my green with an AE composite that forces all the shades of green to only one green. Works great for badly lit stuff. I think some of the newer keyers actually have this code built in, I believe the latest primatte has this. also, a z depth keyer would be easy although the camera would need stereo vision or 2 cameras to create z depth or maybe out of focus would create a matte from pixels not in focus. they're working on that too.

'color punch' technology.
https://forums.creativecow.net/thread/2/1072302


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Gabrielle Dorr
Re: How to fix blonde hair that turned pink after keying
on Dec 3, 2017 at 5:21:13 pm

Thank you for all of your in-depth posts. I am really new to this so was kind of lost with some of the terminology. She is on-screen for such a short time that I just turned down the saturation on the spill suppression and then added color back into her face and hair. There isn't much contrast between her face and hair but I think it will work for my purposes. I didn't realize there was so much art involved in editing!

Also, I didn't take the footage myself but thanks for the tips to set-up better green screens in the future. I can pass that on to the videographers for future shoots.


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