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Keylight Green Screen - Noise on Talent

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Stewart Goldstein
Keylight Green Screen - Noise on Talent
on Oct 29, 2012 at 9:43:23 pm

We have some footage of a gent standing in front of a green screen, which was lit by a pro.

I used Keylight in AE to superimpose the man over some stock footage.

The edges looks good, but the man is wearing a dark suit, which has a lot of noise in it. How can I minimize this? (Reshooting is not an option.)

Since I am a novice, I am including a screen shot, which includes my Keylight settings.

The still doesn't look completely horrible, but during playback, the noise is obvious and distracting.



0_screenshot2012-10-29at4.38.06pm.png


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Darby Edelen
Re: Keylight Green Screen - Noise on Talent
on Oct 29, 2012 at 10:39:43 pm

Noise in keylight is usually caused by the spill suppression. You can try and improve this by adjusting your despill bias, but you may not find a great solution that way. Another option would be to use keylight's Intermediate Result with another spill suppression technique.

Darby Edelen


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Vishesh Arora
Re: Keylight Green Screen - Noise on Talent
on Oct 29, 2012 at 11:19:57 pm

Noise is a common problem with Key-Light plugin.

If you can spend some money, Go for Primatee Keyer.

its a Pro plugin for Keying and widely used in industry. This will give full control on almost everything will keying the Chroma.

Here is the link:

http://www.redgiantsoftware.com/products/all/primatte-keyer/


you can try buy downloading a Trial Version.

Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra

Blog:
http://digieffects.wordpress.com

Demo Reel(3D):







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chris brett
Re: Keylight Green Screen - Noise on Talent
on Oct 29, 2012 at 11:18:34 pm

Hi Stewart

My guess is that it is to do with colour correction / bit depth and suggest you work at 16 or 32 and not 8 bpc ( if you are )..

However there are also a few things worth looking at as below ....



There are two main things here which should not be connected / confused



1 ) The Key

Ive never set up a key thats caused grain ( not saying it cant be done ! ) so this should not be an issue -- if you think its the key change the settings and it should go away.

However - some formats are hard to work with and just because the lighting guy knows his stuff it does not follow that you can always do miracles....

If it wont go away and you still think its to do with the footage you can try treating the footage for the purposes of pulling the key ( this could be useful here as you dont seem to have detailed edges)

The idea is to treat the footage you use for the key ( not the fill ) to remove problem elements - Ive heard of people softening footage to get rid of nasty edges then shrinking the key afterwards to compensate .... the trick here of course is that you use the treated footage for the key BUT fill it with the untreated version.


2 ) The footage --- does the clean footage look ok?

If 'yes' check that there is no compression or colour correction that is causing the problem - remember to adjust shot AFTER it is keyed and not before. ( unless using technique as above )-- for instance increasing contrast can cause grain on images low on picture information.

If you dont have the footage clean from the tape or disc make sure it hasnt been treated before it lands on your desk -- and also that you are getting the footage at the highest possible bpc without any compression


Remember also to look extra carefully at the original ( please excuse the obvious ) - some footage looks ok when its a full frame original but grain and such is sometimes more obvious in the comp as the others elements are 'clean'.


........ so if the key is ok and the original footage is ok then its something that is happening to the footage - such as mentioned above ..........



If your original footage is not great you can try a de-grainer spark ..... sometimes this gives good results

- sapphire have one but I expect theres one in the bundle somewhere ( I'm newish to AE myself ) -- and if not someone else will probably know whats best for this anyway

- de-grainers are not magic and need setting up carefully but they do help .... they dont however, in my experience, completely get rid of the problem but they can make it so ' you dont notice it '.




In summarising I would definitely say that if I were you I would have the key and the fill as separate items and treat them completely independently -- ie use footage to do whatever you have to to get a clean key then fill it with a duplicate layer of itself.

The purpose of this is to keep adjustments required for the key completely separate from any colour correction you make to the image to make it look right in the comp.

---------------------- chris brett // U K


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Roland R. Kahlenberg
Re: Keylight Green Screen - Noise on Talent
on Oct 29, 2012 at 11:34:52 pm

You should de-grain your footage prior to the actual keying process. Then, as Darby has suggested, do not use Keylight's Final Result but instead use its Intermediate Output (these options are found under the View drop-down menu).

It's also a good idea to use the Keylight layer as a matte for the original footage. Again, de-grain the original footage if it's grainy beyond your liking.

HTH
RoRK

Intensive mocha & AE Training in Singapore and Other Dangerous Locations

Imagineer Systems (mocha) Certified Instructor
& Adobe After Effects ACE/ACI (version 7)


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Dave LaRonde
Re: Keylight Green Screen - Noise on Talent
on Oct 30, 2012 at 2:25:07 pm

...and here's a third way that can help:
  • Duplicate the green screen shot. Add Keylight to the upper layer.
  • Using the Status view, pull what you know to be a good key: gray at the edges, white at the core, don't worry if parts of the white go green. Change the view back to Final Result.
  • Use the upper layer as an alpha matte for the lower layer. If you need spill suppression, use AE's own built-in Spill Suppressor.
  • Tweak the upper layer key to resolve any edge problems
.

Dave LaRonde
Former Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Anthony Marzilli
Re: Keylight Green Screen - Noise on Talent
on Oct 30, 2012 at 3:20:14 pm

I second Dave. Thats what works best for me.


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Darby Edelen
Re: Keylight Green Screen - Noise on Talent
on Oct 30, 2012 at 4:57:43 pm

Quick tip: the intermediate result from keylight should give exactly the same result as using the keyed footage as a matte. Only you get it all on one layer!

Darby Edelen


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Oliver de Morassé
Re: Keylight Green Screen - Noise on Talent
on Nov 26, 2012 at 1:17:41 pm

Nice tip Dave. For clarification, should keylight also be applied to the lower layer or any other effects - like spill suppressor?


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Dave LaRonde
Re: Keylight Green Screen - Noise on Talent
on Nov 26, 2012 at 3:16:39 pm

Darby recently posted a really nice recipe he uses for spill suppression, using one of AE's Channel effects. You could search for it.

So now you'd have three options:
  • Apply Keylight to the layer and tweak settings for spill suppression only
  • Use AE's spill supressor
  • Use Darby's trick


Dave LaRonde
Former Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Oliver de Morassé
Re: Keylight Green Screen - Noise on Talent
on Nov 27, 2012 at 12:12:00 pm

Thanks Dave. Here is the link to Darby's tip.
. Sorry to sound a right dummy, however, I am just learning AE. For clarification, everything is done to the upper layer (keylight, colour correction etc.). What's the bottom layer for - what should I do with it?


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Dave LaRonde
Re: Keylight Green Screen - Noise on Talent
on Nov 27, 2012 at 7:17:45 pm

Duplicate the bottom layer. You know have three copies of the same shot, 2 with Keylight applied. Move one of those Keylight layers ABOVE the channel effects layer and use it as an alpha matte for the channel effect layer. You do it in the channel effect layer.

Look up the topic of Track Mattes in AE's online help.

Dave LaRonde
Former Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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