Can you help me with this chroma key?

[Topher Welsh]

Well for starters you can probably mask out the desk so that doesn’t get touched, that is only if you are using a tripod and the camera is steady.

as for the shadows underneath the ears… I would color correct the shot, and then I would just fool around with the clip black and clip white settings in Keylight until you get the desired result.

Topher Welsh
Head Editor & Motion Graphics
http://www.scout.com

[Alfonso Gamez jordano]

But wouldn’t it be quicker (if possible) to play around with the different keyed comps, maybe precomping them separately, and afterwards using them as layer mattes for the original source?

As to tell after effects, “show me, from the source layer, comp 1’s black minus comp 2’s black, plus the other’s white, or something like that?

Cheers

[Darby Edelen]

[Topher Welsh] “I would color correct the shot, and then I would just fool around with the clip black and clip white settings in Keylight until you get the desired result.”

To clarify, you should never color correct anything before your key. Only color correct after you have a satisfactory key.

As for your problem, I would suggest using at least 2 and maybe 3 different instances of your footage. Mask the table loosely in the first so that it is the only thing visible and then run Keylight to get rid of the remaining green. The point here is to use settings that make the table and only the table look good. Next for your 2nd instance you can mask the subject and use keylight to remove the green around him, it doesn’t matter if the table looks bad in this case because we have a good key of the table in instance one.

You might find that you need to do this a few times, but it should give you good results. I’d also recommend looking at using keylight to generate a core matte and an edge matte for better results, but that’s more advanced and may not be necessary in this case.

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[Topher Welsh]

[Darby Edelen] “To clarify, you should never color correct anything before your key. Only color correct after you have a satisfactory key.”

Is this the case even if you has unsatisfactory lighting and not-as-great-as-it-could-be green screen in the background? I would think that if you color corrected, you might be able to generate a better key…

Sorry for the false information Darby, just trying to help… but thats why were on this board right? to learn…

Thanks for the info though!

Topher Welsh
Head Editor & Motion Graphics
http://www.scout.com

[Darby Edelen]

[Topher Welsh] “Is this the case even if you has unsatisfactory lighting and not-as-great-as-it-could-be green screen in the background? I would think that if you color corrected, you might be able to generate a better key… “

Since chroma keying algorithms work with the color information in an image, it’s not advised to change that information before trying to use it for a key. Generally if you try to remove green from the foreground, you will also end up removing green from the background. If you try to make the background greener then the foreground will also become greener. You could potentially make the color corrections based on a matte, but if you’re already going to the trouble of matting for the color correction then the color correction becomes somewhat unnecessary (or at least less useful than the matte).

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[Erik Pontius]

I took a stab at just keying the sample image that you supplied with keylight.
https://www.burningfromice.com/keylight/keylight.htm

Not perfect, but passable…so it is possible. You’ll just have to fiddle with it.
My keylight settings are also included on the page.
I used two masks. One is just to eliminate the sides that weren’t covered by the greenscreen. The second was to eliminate the object in the foreground next to the desk…I set the mask mode to “none” and then used the Outside mask option in keylight to use this mask to remove the object.

Have fun.

Erik

[Alfonso Gamez jordano]

Thanks everyone, finally, I’ll test Erik’s settings, and if they work for me well (which I suppose should happen) I’ll stick to them, as I actually liked the little shadows it left near the neck, they look somehow like hair 😀

I’ll test them and I tell you

Thanks again to all of you =)

[Barend Onneweer]

[Darby Edelen] “Since chroma keying algorithms work with the color information in an image, it’s not advised to change that information before trying to use it for a key.”

It really depends on the keying algorithm used. For instance, Keylight really seems to work best in a gamma 2.2 situation.

In reality this can mean that flat (low contrast) or under or over exposed footage isn’t keyed very well.

I’ve just finished 6 weeks of compositing on a project shot using the new RED camera. The footage was shot a little flat to preserve highlights, and the material came in as linear data (gamma 1.0).

Color profile conversion and color correction prior to keying really improved the keying quality in Keylight dramatically.

Bar3nd

Raamw3rk – digital storytelling and visual effects