ADOBE AFTER EFFECTS: Forum Expressions Tutorials Creative Cloud

Keying: Blonde Hair and Graininess on Black Shirts

COW Forums : Adobe After Effects

<< PREVIOUS   •   FAQ   •   VIEW ALL   •   PRINT   •   NEXT >>
Ben Grace
Keying: Blonde Hair and Graininess on Black Shirts
on Apr 1, 2011 at 7:28:55 pm

Hey guys-

Second time posting here. Basicaly I'm interning for a motion graphics company and have never used After Effects before. I am doing a keying assignment for some dancers that is actually pretty easy- Camera doesn't move and theres no shadows in the background.

However I'm encountering a bit of a weird problem- the video seems to have a bit of a moving grain when the video plays. I tried to show this in the picture below, but it's a little tough to show in picture format.

Secondly, I'm trying to key some shiney blonde hair/strands of hair on these dancers. I'm really only familiar with the keylight effect..but maybe there is something else I should do? If you all could, maybe explain your response in a little more detail/dummy terms. I'm still getting acclimated and have trouble with some of the posts on the site.

http://i6.photobucket.com/albums/y228/megamustaine1338/Example1.jpg

http://i6.photobucket.com/albums/y228/megamustaine1338/Example2.jpg


Return to posts index


Ben Grace
Re: Keying: Blonde Hair and Graininess on Black Shirts
on Apr 1, 2011 at 8:24:51 pm

Trying to figure out how to edit my thread: my coworker actually showed me a pretty cool trick, somehow using the clip white as a mask? Not sure but basically he told me to copy the video and put it above on Screen Matte.

Then below it on the original video, delete the keylight and change it to the luma alpha chanel. This solved my grain problem (just have to do it to all 60+ video files) but the blonde hair is still an issue. Also, maybe you guys can give a name to what he showed me..was really useful!


Return to posts index

Dave LaRonde
Re: Keying: Blonde Hair and Graininess on Black Shirts
on Apr 1, 2011 at 8:52:26 pm

Pulling a good key requires a few things: 1)( good lighting, a 2) good recording medium, and 3) knowledge of the keyer you use.

1) The lighting looks good on the subjects, and the green screen looks like it's uniformly-lit. No problem there.

---------------------------------------------------------

2) What kind of camera was used to shoot the video? More specifically, what was the acquisition codec? In order to get ten pounds of you-know-what into a five-pound bag, certain acquisition codecs cheat on recording color information it happens in the color sampling (aka color resolution). If you're shooting on a a DSLR, HDV camera, XDCam, FlipCam or the like, you've got lousy color sampling going on, making it especially tough to get a clean key on edges and fine lines... like hair.

Take 15 minutes to watch this podcast. It's a great non-technical explanation of color sampling:






Pay attention to the DV example near the end; the color sampling in DV is just as lousy as it is in the cameras I mention above.

---------------------------------------------------------

3) If you're trying to use Keylight intuitively, you'll have problems. End of story. It requires knowledge of how it works. You need to search the COW's AE tutorials section and look at the material on keylight. You'll find it. You should also go to The Foundry's web site and download the Keylight User Guide and example footage for the tutorials. The Foundry makes Keylight.

---------------------------------------------------------

Your buddy's suggestion about using one one the view modes in keylight may be okay, but I do it differently: pull a good-looking key with nice edges and no holes in the core, and screw the noise in the blacks. Then use this layer as an Alpha Matte for a duplicate layer of the footage without keylight applied.
If you see a little green spill in the result, you can always add keylight to the bottom layer, and tweak with the settings until the background goes grayish. If the status view is almost all white, that's fine: you've got spill suppression but not a key; you have the layer above as a track matte.

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


Return to posts index


Ben Grace
Re: Keying: Blonde Hair and Graininess on Black Shirts
on Apr 1, 2011 at 9:00:40 pm

Thanks for the quick/incredibly helpful response Dave. Learning AE on the spot while trying to do work for a company has proved to be a challenge.

As you mentioned, doing the technique that my buddy suggested has worked well, except for dancers/players with long hair. There is some green that bleeds through on the back near their hair. I tried putting keylight on both copies of the video, but it doesn't seem to work. For now, i'm going to continue composting the players with short hair that his trick does work, and hopefully figure out a work around for the dancers.

Also I really thank you for those links. THe problem I'm having with most tutorials is that they aren't in depth: so many keys have so much difference. I watch a tutorial of someone simply keying out footage with no trouble. But then I'll get video that is much trickier/different to key so I haven't had a great chance to get acclimated. I'll check out your links- if they provide video footage hopefully that can give me a better understanding of keying!

Also, I apologize for my 'n00bness'. It's always an adjustment period when you begin on a journey doing something you've never done before. I'm into guitar, animation, and now motion graphics; each time i dived into the community i always felt very stupid at first but after learning terminology and etc, learned a lot.

by the way, i'm not sure what the footage was shot with. We have some nice gear here: realme.com has the full list of cameras and etc, but its 1920 x 1080 and 30 fps. Also: I am working on implementing what you suggested but having a little trouble understanding exactly what you mean.

I'll explain in more clarity what my co-worker suggested (again, which works except bleeds a little green through the back of some people)

1. Duplicate the Keyed video layer
2. Delete the keylight on the original video and keep it on the duplicate. Change the original to a luma matte.
3. Turn the duplicate to screen matte and turn its eye off.

What you suggested, would I follow similar steps but select alpha instead of luma? The actual keys look great, absolutely no white in the center of the person (probably due to good lighting/a clear green screen.) You mentioned to get a good key (which I did) and use it as an alpha layer. I tried duplicating my good key, changing the original to alpha, and deleting keylight on the duplicate. However it doesn't seem to be doing antyhing, or going to straight white. Again, sorry for lacking knowledge in this area, i'm sure it makes it harder to understand what i' talking about.


Return to posts index

Dave LaRonde
Re: Keying: Blonde Hair and Graininess on Black Shirts
on Apr 4, 2011 at 6:13:15 pm

[Ben Grace] "What you suggested, would I follow similar steps but select alpha instead of luma?"

Correct. In fact, I suspect that 1) your coworker intentionally misled you to see what you'd do or 2) you misunderstood your coworker. it SHOULD be alpha instead of luma. And don't use a screen blend mode.

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


Return to posts index

Ben Grace
Re: Keying: Blonde Hair and Graininess on Black Shirts
on Apr 5, 2011 at 2:26:27 pm

ANy idea what to do if there's significant green bleed on the back?


Return to posts index


Dave LaRonde
Re: Keying: Blonde Hair and Graininess on Black Shirts
on Apr 5, 2011 at 3:02:39 pm

Yup, I already described how to handle light spill. Go look again at the posts.

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


Return to posts index

Ben Grace
Re: Keying: Blonde Hair and Graininess on Black Shirts
on Apr 5, 2011 at 3:16:21 pm

Thanks Dave- yeah I did read what you wrote but didn't quite understand it. When I apply keylight to the bottom layer (the alpha layer) and change it to have a greyish background, you can see the grey on the person's face. I know this is annoying to answer questions for someone as new to this as me. To top it off, my boss just told me this is due in an hour and a half...my co worker suggested oolor correction to find the greens and desature them- i did that but you can still see quite a bit of green. I'm going to keep trying your method but i'm obviously doing something wrong.

edit- i realize what you wanted me to do dave. This issue is when i do the keylight plugin on the alpha matte, i get the grain on the image when it plays. I just applied it to all the video and then played them and realized it basically nulls out the alpha matte. What settings would I tweak to get it to be grey? I have it keying out the green, but maybe it should key out something else?

edit 2- on the second key on the alpha, i replaced the color with a much lighter green. Not sure why, but that seems to remove a lto of the green and the grain. Key still isn't perfect, but i think my boss/client will hopefuly accept it.


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]