So we make all these rad 3d backgrounds for some bluescreen footage, but when receiving the footage, we realize that the edges have not been cut out very well!
Check below:
There is no clever way to recover the edges from footage that looks like this, because all the blue has been taken out. So we use the original bluescreen footage to better define the edges. The original image below has much more information we can use to separate the foreground and background.
Unfortunately, there is blue light spilling everywhere!! This makes things more difficult, and is probably the reason why the keyed footage returned a poor result.
The next task is to make a matte for our footage, I chose to use Selective Color in 'Absolute' method as it returns a good result. I also sometimes use the "Black & White" filter in a similar way to isolate colours into a grayscale image.
With a bit of levels, we can turn this into a good starting point for our 'luma matte' mask
A few masks on a black solid help to clean up with areas that are static during our shot.
Add invert on an adjustment later (its not really necessary, but it helps me see the mask better)
HHere is the original cut out footage with messy edges.
We set it to Luma Matte (using the black and white composition we just made) and the edges are immediately much better!
Looking at it with the 3D elements in the scene aswell reveals a problem though..
This is not so bad - actually its only showing through in the reflective areas of our objects, the areas that reflected blue. In our 3d environment they should actually be reflecting something with similar lighting to the background.
So duplicate the background layer and blur it,
And set it to alpha matte of our original badly cut out footage.
If you don't have badly cut out footage (why would you), you can make your own.
Just take the black and white image and levels it till you get a half decent situation :)
