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How to remove unwanted shadows with green screen footage

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Oliver de MorasséHow to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 11:43:29 am

I am having problems removing shadows from my green screen footage. Here a few screenshots:

The original footage
Using keylight & screen matte
Using keylight & Final Result
Project Settings

The shadow around the feet is my problem - what's the best way of tackling this problem? At the moment I just have the one layer with my keylight effect applied. Thanks for any tips.


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Vishesh AroraRe: How to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 12:16:29 pm

Oliver

You can create a Garbage Matte around the feet to avoid shadows.

See the tutorial:

Creating Super Tight Junk Mattes

You can skip the Autotrace step and animate the Mask Path if your character is not moving too much as autotrace will take sometime to work on.

See the example:
5146_garbagematte.zip

Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra

Blog:
http://digieffects.wordpress.com

Demo Reel(3D):







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Vishesh AroraRe: How to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 12:29:07 pm

Another example using Autotrace:

5147_garbagemattepart2.zip

Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra

Blog:
http://digieffects.wordpress.com

Demo Reel(3D):







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Oliver de MorasséRe: How to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 3:40:15 pm

Thanks Vishesh. What I have noticed is that you use the "Color Range" along with "Simple Choker" effects before Keylight - any reason?

This spokesperson walk on/off the screen - can autotrace still work here across multiple frames of movement?


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Vishesh AroraRe: How to remove unwanted shadows with green screen footage
by on Jan 3, 2013 at 7:48:26 am

Oliver

With Color Range you can select range of colors to key out. In this case Shades of Green.

This is somewhat similar to using Color Key several times.

Simple Choker is used to create a Garbage Matte and then finally Keylight with little adjustment.

Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra

Blog:
http://digieffects.wordpress.com

Demo Reel(3D):







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Roland R. KahlenbergRe: How to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 1:02:43 pm

MEH!? He doesn't look like he's about to dance - a basic Mask routine should do and even if he did do a bit of a song and a dance, Roto Brush should handle that nicely.

Look at working to create procedural mattes. In this case, break up the final, required matte based on two 'working mattes'. One above the problem area and another below it. The area with the problem only needs a different keying parameter setting.

A good tip when keying is to use the ALT key to obtain a sorta WYSIWYG (what you see is what you get) aka realtime feedback of which areas will be keyed and the intensity of the key. Add the CTRL key to use AE's 'fattened' eye-dropper tool which samples a larger number of pixels for the keying process. This almost invariably results in better keying at the onset.

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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Oliver de MorasséRe: How to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 3:49:27 pm

Thanks RoRK for your feeback. The spokesperson walks on/off the screen - never used Roto Brush - will this work and any tips?

You have kind of lost me regarding the whole procedural mattes thing - any chance of supplying a rough AEP so that I can look at exactly what you mean.

Great tip regarding the ALT & CTRL keys when keying - thanks.


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Stefan HinzeRe: How to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 1:10:21 pm

Hi,
this is a mixture of
- multiple COLOR KEYer
- MATT CHOCKER (shrink)
- MATT CHOCKER (expand)

Don´t ´let the Noise (there will be a lot!!!)
distract you. You will get rid of the nois
if you use THIS as a Matte!

I hope this helps!



Here is the AEP (german... sorry, you´ll need to relink/rename the FX´n´Stuff...)

5148_key.zip

(take a step back, to see the bigger picture)


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Oliver de MorasséRe: How to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 4:13:13 pm

Thanks for your feeback Stefan. Very interesting workflow, and just for clarification a few questions:

1. Why do you start with "color key" for the basic keying and not straight away with keylight?

2. Why do you use "simple choker" shrinked and then expanded?

3. Your AEP has 2 compositions - Key & Final. Please can you explain a little regarding what you are doing here. From what I understand, the "Key" is where you do the original keying which produces a relatively noisy result. You then created a new "Final" composition and brought the keyed "Key" composition into it. The original footage is used as a Alpha Track Matte and is the parent for the "key". If I need to do any color correction, should I be doing this in the "key" or "final" composition.

I am new to this... go easy with me ;O)

Thanks again.


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Stefan HinzeRe: How to remove unwanted shadows with green screen footage
by on Jan 2, 2013 at 5:29:00 pm

Hey,

The COLOR KEY is fast and you can "stak" them a cupple of times!
MATTE-Choked - to get rid of some filckering stuff between the feet (shut them of one by one, you will see!) - and then i expand, so i get the person back and have a "border" i can key from.
Thats a simple and tight garbage matte like Vishesh Arora mentioned.

Then i used the KEYLIGHT FX to do the "real" keying. But even KEYLIGHT did the "Clean" key, COLOR KEY makes the way clear, whitout (in your case) COLOR KEY, it would be mutch harder to let KEYLIGHT do its thing!

Go to Keylight and set the output to MATTE, then play with the values.
You will see, it´s no big space to play, and the shadow can popup some times... well, in that case, just try to use another COLOR KEY.
(maybe you well need to cut the clip, so you don´t effekt more (in time) than nessaserry)

(sorry for my missspelled english!)

If you go the way i did, you end up with a lot of noise --> ColorKey
Thats why i set the KEYedComp as a Matte in the FINAL-Comp, this way you get rid of the Noise! I parrented them, so if you move, scale or rotate... the layer, the matte stays put!
(is it legal to say PUT in this sentens? ;) )

Here is in short the way i did it:

COMP 1 "Key"
- COLOR KEY the hell out of it ;)
- IF you have little flickery things in the shadow - try MATTE CHOCKER (shrink the matte)
- Use MATTE CHOCKER and expant the matte again, the flickeriy stuff should be gone! Expand the Matte even more, so you end up having a greeg outline!
- Use KEYLIGHT to finale Key the person. i-dropper first,(Set the "View" to SCREEN MATTE) then use the sliders and finetune.
(PREVIEW the clip, a still is not relyable in keying! ;) )

COMP 2 "Final"
- Import Comp "Key"
- Import the clip (no precomp needet)
- Sync, time, position, rotation... n stuff!
- Parrent
(read the * below)
- Use the Comp "Key" as Matte for the Clip

*Start in the FINAL Comp, import the Clip, select, CMD+D, you should have 2x the same clip, selekt one, CMD+C (PreCompose), parrent.
This way arround you are faster!


I hope this helps!
;)


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Oliver de MorasséRe: How to remove unwanted shadows with green screen footage
by on Jan 3, 2013 at 10:11:37 am

Thanks for all your tips. I have experimented a little and come up with a reasonable result. However, I have found that when I take too much shadow away then I start to loose details i.e. shoes appear to shrink & hair begins to vanish. Please see following:

AEP Project
Feet - Original
Feet - keyed
Head - Original
Head - Keyed

Any tips? Do I need to mask each area separately and then apply the effects - what's the best approach.

Thanks again for all your help / advise.


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Stefan HinzeRe: How to remove unwanted shadows with green screen footage
by on Jan 3, 2013 at 1:06:17 pm

Hi,

try to cut the key in half!
Maybe you can only key the foot-shadow and key the rest like you would normaly, then join the 2 keyed images?!

;)

(take a step back, to see the bigger picture)


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Oliver de MorasséRe: How to remove unwanted shadows with green screen footage
by on Jan 3, 2013 at 5:16:14 pm

Not sure what you mean by cutting the key in half?!?!

Have tried to create an additional mask around the feet, then duplicated the layer and played with the effects on both layers. However, had problems joining both keyed layers together - the blending between both layers does not look good.

Am I going about this right? Any tips? Would be great if you could do a rough update of the AEP so I could see how this is best done.

Many thanks.


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Stefan HinzeRe: How to remove unwanted shadows with green screen footage
by on Jan 3, 2013 at 5:20:02 pm

Easy,

select both layers, press F (feather) set the value to... 10 oder 30 oder.. what ever looks good.

Did that wolked?

(take a step back, to see the bigger picture)


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