Expert Keying with Keylight 1.2 in After effects

For Video Production, Greenscreen is an important part of producing media, it is used in video interviews and films. Understanding the basics of keying in after effects is a must for any digital media producer.
This tutorial is a no-nonsense approach to getting good results with your green screen media.
To follow along with the tutorial, you must have experience with layers and masks.
I do not go into detail on how each setting works, just guide you on getting a good result.
When working with Keylight, only work with intermediate result and status view.

Garbage Mask
Add a mask to hide unnecessary footage that is outside of the keying(green screen area) area.
Go to Effects & Presets, Key light 1.2 + Key cleaner + Advanced spill suppressor

Screen colour:
> Open up Layer view and Comp view side by side
> In comp view in keylight settings set to status view
> On the layer view hold Alt and hover over the keying area
> Choose colour contrast that is more white vs black (not grey if there is no hair or fine objects in the scene)
> If hair is present in scene choose a compromise with grey and black.

Keylight Screen Matte Settings:
> Clip black: low value is best to hide grey artefacts in status view (1-10)
(Leave clip black alone if hair is present in the scene.)
> Clip white: reduce to remove grey artefacts in the white area.
Note * high number range difference between clip black and white is best.
A lower range difference is not desirable.
> Screen Softness: Set between 0 – 2.
> Shrink/grow: is set to half of the screen softness value.

Help to Refine Matte:
Create a new layer (set as non-render)with gradient ramp effect and add below key layer ( use swap colour in gradient effects to see differences )
Use real background as reference also.
This will help you see more artefacts in the keying area, as black or transparency background may allow some to be missed.

Color Spill(green color spill /shading around the keyed subject)
Advanced spill suppressor: Standard can work best , if Ultra is needed (with blue screen) use first 3 settings and find a compromise between the number ranges.

Key Cleaner ( if needed )
Key Cleaner effect used to soften edges, set to 2 – 3