EX7: Keying

What is Keying?:

What keying is, it to separate objects in your shot from the green screen, we are able to do this with the use of video editing software, like After Effects. We use green for the editing process as green shows up a lot less than blue or red on our skin, and its easier to identify what the software has to be removing and keeping.

Why do we separate the footage in to separate keys?:

This is because different areas of the subject that you are keying can react differently to the green screen.

Why are alpha layers so important?:

The alpha channels are for changing the transparency of the image, for example, if it is black, then it is completely transparent, whereas if its white it is solid, we can find a good mix in between these values to make your subject semi-transparent. This is useful in removing the white outlines left by the lighting in the subject we are keying.

Why do we need to despill?

This is known as the process of removing the green that has spilled on the subject, and by doing this we can make the footage look more realistic. (I can’t think of any human with a green glow.)


What are light wraps used for?

This is to make the subject blend into the background by making the lighting of the background hit the subject, thereby making it more realistic.

My attempt:


First I removed the grain from the image to make the entire process more easier on myself. After I that I selected the pen tool and started using it around the area of her legs, to separate parts of the subject, and animated the mask every now and then so the subject would not move out of place.


I then applied the footage to the timeline.


I repeated this process except now for her torso and head.

Then after masking everything that needed to be masked, I used KeyLight to separate and remove the green backgrounds.

After that, I composited the background into the footage, and using the curves to colour correct the subject so that they would match and blend in with the background lighting, making it appear more realistic.


And here is the final result:


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