I shot on white bg
by Michael Gug
on
Jun 4, 2008 at 12:39:22 pm
Hi,
I shot a few CU's from the chest up of some actors. I did this on a white BG with intentions of removing the white bg in post. I have seen people use this with as good a result as if it was shot on a green/bluescreen. But I can't get rid of the spill in the actors hair. There is a white line around their head.
How do I get rid of this white line and completely seperate my actors from the bg?
Re: I shot on white bg by david bogie on Jun 4, 2008 at 2:14:52 pm
All good chromakeying requires several filters and maybe stacked copies of the footage with different filters and masks. Keying out white is supremely difficult with standard video formats; you have not mentioned which format you're working with.
bogiesan
This is my standard sigfile so do not take it personally: "For crying out loud, read the freakin' manual."
Re: I shot on white bg by Dave LaRonde on Jun 4, 2008 at 3:07:48 pm
[Michael Gug]" But it seem that keylight, wont work on white bagground, any reason why?"
Because keylight is designed to work primarily on blue or green baggrounds.
If you shot this footage IN HOPE of it turning out right, rather than KNOWING you could make it turn out right, read on:
Dave's Stock Answer #2:
When you're out on a shoot, and you say, "we'll fix this in post" without knowing PRECISELY HOW you're going to fix it in post, don't shoot it! You'll only end up shooting it over again.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: I shot on white bg by Jessica Duenke on Jun 4, 2008 at 3:15:59 pm
Hi Michael
I do agree with Dave, make sure that you have a plan for post before shooting.
I have been able to "key" a white background before, but it will depend on what your footage is like. If you duplicate your footage layer in your comp, make the top layer high contrast black and white to use it as a track matte for the layer below. That way you don't have to worry about messing up your actual footage or worry about keying out lighter parts of the actor. Again, it will depend on what your footage is like, but it may be what you are looking for.
Re: I shot on white bg by Jessica Duenke on Jun 4, 2008 at 3:25:23 pm
Hi Michael
I agree with Dave, pre-planning for post is ESSENTIAL!!
Since you are stuck with what you have, one thing I have done with getting rid of a white background is to duplicate your footage layer and create a track matte from it. Usually there is enough contrast between the actor and the white background, but it will depend on what your footage is like.
Re: I shot on white bg by Kevin Dearing on Jun 4, 2008 at 5:26:01 pm
Another idea is to see how well you can use a luma key... Probably throw a levels or curves (or both) effect on the footage first to brighten up the background and make sure that the "talent" still looks properly exposed. May not work depending on your footage..
But I'm sure that's not really where your problem lay.. You mentioned that the spill is what your problem is.. That, I'm afraid to say, is not what this Noob knows how to handle with good results yet. I normally just try to do the same thing 5 different ways and see which gives the best results (in the best time)..
Re: I shot on white bg by Darby Edelen on Jun 4, 2008 at 6:43:39 pm
[Michael Gug]"But it seem that keylight, wont work on white bagground, any reason why?"
Keylight is a color difference keying solution, it requires that there be a strong primary color in the background (usually green/blue).
You're dealing more with a luma key. In your case you'll want to push the background further into white and bring the foreground closer to black, then invert the image and use it as a matte... Something involving Levels/Curves, Tint and Invert perhaps.
Darby Edelen Lead Designer Left Coast Digital Santa Cruz, CA
Re: I shot on white bg by Ron Coy on Jun 4, 2008 at 4:14:49 pm
have you tried the Simple Choker or Matt Choker effects? I used this once to get rid of the slight edge left from a premultiplied shadow next to a transparency.
see if it works.
Also, check out spill suppressor under keying in the effects menu. That's what it's for.
Re: I shot on white bg by Grant Swanson on Jun 4, 2008 at 10:22:44 pm
Hi Michael,
For keying white you almost always want to use the "Extract" keyer, not "Luma." Just drag in the top right point, and then drag the bottom point back a little to smooth it out. If you're still having problems with your edges just apply a Simple Choker or a Matte Choker.
Re: I shot on white bg by david bogie on Jun 5, 2008 at 5:47:18 pm
> For keying white you almost always want to use the "Extract" keyer, not "Luma." Just drag in the top right point, and then drag the bottom point back a little to smooth it out. If you're still having problems with your edges just apply a Simple Choker or a Matte Choker.
But it won't be "simple" at all. If there's any luminance value in your foreground that comes close to your white, it will key out also., that's why you will need to stack copies of your foreground image. Say the guy is wearing a white tie. You will need to mask out the tie on an upper layer. Chokers will not take care of your hair issues all by themselves.
the OP may be confusing a "white void look" with shooting on and then keying out the white.
I'd reshoot it or redesign the project based on what you know will work instead of what you had hope might work.
bogiesan
This is my standard sigfile so do not take it personally: "For crying out loud, read the freakin' manual."
Re: I shot on white bg by Darby Edelen on Jun 7, 2008 at 12:04:43 am
[david bogie]"I'd reshoot it or redesign the project based on what you know will work instead of what you had hope might work.
"
In the same spirit as that, you could still have your talent wear a white tie if you make sure that it's not as white as the background... perhaps by running it through some dirty water or whatever else you can do to make it pop less. This also requires forethought, but should also allow you to use the same technique as you started with if you're set on using a white background.
Darby Edelen Lead Designer Left Coast Digital Santa Cruz, CA
