Keylight:
Developed by the Computer Film Company
Ported to After Effects by The Foundry
The Foundry:
Based in Soho London, The Foundry specialise in developing plug-in visual effects for compositing platforms in the film and video post production industry.
Here is a good series of Keylight tutorials, here they are using 'Nuke' but the principle is the same:
Tools developed at The Foundry:
Nuke is an Academy award winning compositor from The Foundry.
Tinder plug-ins have been developed by the Foundry and have been sold to hundreds of users throughout the world. They are available on the leading compositing platforms including Discreet Frame, Avid DS, Shake and Adobe After Effects.
Furnace is a collection of image processing tools using motion estimation technology to help compositors tackle common problems when working on films. Plug-ins include wire removal, retiming, rig removal, texture plug-ins, grain management, steadiness and deflicker.
Anvil is a set of colour correction and colour manipulation tools.
Chroma key Glossary
Alpha- The Alpha value of an image or movie contains transparency information.
Matte- The mask used to create a value of transparency for compositing
Key- To use a Matte to composite more than one image.
Screen Gain-
This boosts or reduces the saturation of the RGB value of each pixel before applying the screen colour.
This means that if there are desaturated greens in the background, by boosting the gain more pixels will be included in the matte.
Inversely, if the gain is reduced, any peels in the foreground containing the background colour may be knocked back.
Be careful with the Screen Gain, if over-used subtle image information such wispy hair or motion blur can be lost.
Screen Balance-
The screen balance deals with the purity of the chroma (how green is your green screen?). Keylight will default a green screen to 50% and bluescreen footage will be set to 95%.
The balance can be adjusted to reflect the about of red and blue in the greenscreen or the amount of red and green in the bluescreen.
Screen PreBlur-
This will blur the image before the key is pulled, therefore creating a softer, less grainy screen.
Despilll Bias-
Sometime there will be screen overspill into the foreground, this can be caused by the screen colour reflecting back onto the foreground subject. Despil bias can reduce the green or blue cast.
Clip Black/ Clip White-
These will increase the contrast of the screen matte. In other words, this tool will use the luminance values of the image to influence the matte.
Screen Dilate-
This will do a dilate or an erode the finished key.
Screen softness-
This will blur the image AFTER the key has been pulled.
Screen Despot Black-
This will remove floating white pixels from the black matte and floating black pixels from the white core key.
Screen Matte - this renders the matte created by picking the screen colour.
Status - this renders an exaggerated view of the mattes so that minor problems are shown clearly.
Final Result - this renders the foreground composited over the background using all mattes, spill and colour corrections.
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