Premiere Pro CS5

[Kevin Monahan]

Did you shoot them against a blue or green screen? If so, then it’s very possible. If not, you’ll need to rotoscope. Not a whole lot of fun.

Kevin Monahan
Sr. Content and Community Lead
Adobe After Effects
Adobe Premiere Pro
Adobe Systems, Inc.
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[Jason Bradford]

I am not really acquainted with rotoscoping. I have not shot it yet, it is just conceptual at the moment. I can shoot against a greenscreen and key the green out, but I cannot figure out how to remove the internal part of the image to reveal the layer underneath, I suppose I am still a little green myself when it comes to this sort of thing.

[Alex Udell]

the process of removing the green is called chroma keying.

chroma keyers are tools that use a combination of controls (i.e. parameters) to determine the level transparency of a pixel in an image

based on the settings, the chroma keyer internally creates what is called a “matte” (or alpha) where:

pixels that are meant to be opaque are set to white,

pixels that are meant to be transparent are set to black

and those that are meant to be semi-transparent are set to some level of gray between black and white accordingly.

most keyers have a setting where you can see not only the result (your original image minus the green/blue) but the matte output as well.

as such, by simply “INVERTING” the matte or the key, a control found on keying fx, the matte negates itself and the opposite pixes become transparent..(black becomes white and white becomes black in the matte)

thus if you shot someone against a blue or green screen, keyed out the green, then INVERTED the key, the key hole would be inside the matte instead of outside the matte.

so you could do an inverse key on a higher video track and put your filling image on a lower video track….

now if you want to key the green, fill the matte, and still place the whole thing over some other background….that gets a bit more complicated, but that can be done too…much of it in Premiere Pro too.

However, if you get into a much more detailed level of work, you might consider moving the project in to After Effects. It’s controls are geared much more for pixel level polishing.

Hope this conceptually helps…

Alex

[Jason Bradford]

Thanks, Alex. That is exactly what I was endeavoring to do. That was great detail in your tutorial, now I will need to embark on the last step you spoke of: “key the green, fill the matte, and still place the whole thing over some other background.” Hopefully, can get that one perfected, as well.

[Netta Sad]

Jason,

Did you ever figure this puzzle out? I am trying to do the exact same thing using Premiere Pro CS6. I’m searching for somewhere to reverse a matte… no luck yet…

[Jason Bradford]

Yes and it worked beautifully. This is what I learned form Alex Udall:

the process of removing the green is called chroma keying.

chroma keyers are tools that use a combination of controls (i.e. parameters) to determine the level transparency of a pixel in an image

based on the settings, the chroma keyer internally creates what is called a “matte” (or alpha) where:

pixels that are meant to be opaque are set to white,

pixels that are meant to be transparent are set to black

and those that are meant to be semi-transparent are set to some level of gray between black and white accordingly.

most keyers have a setting where you can see not only the result (your original image minus the green/blue) but the matte output as well.

as such, by simply “INVERTING” the matte or the key, a control found on keying fx, the matte negates itself and the opposite pixes become transparent..(black becomes white and white becomes black in the matte)

thus if you shot someone against a blue or green screen, keyed out the green, then INVERTED the key, the key hole would be inside the matte instead of outside the matte.

so you could do an inverse key on a higher video track and put your filling image on a lower video track….

now if you want to key the green, fill the matte, and still place the whole thing over some other background….that gets a bit more complicated, but that can be done too…much of it in Premiere Pro too.

However, if you get into a much more detailed level of work, you might consider moving the project in to After Effects. It’s controls are geared much more for pixel level polishing.

Hope this conceptually helps…

Alex