Chroma and Luma keying is available on visual resources (Images, Video Capture and Movies) and is typically used for masking out areas or green screen applications.
Chroma Key
This is available for, and sets which colour will become transparent to layers below, and is most usable on multi-coloured media (not monochrome), since you pick a colour and tolerance / range around that colour.
Colour
Choose which colour will be transparent.
Tolerance
0 means the exact colour only will be transparent, higher numbers will allow similar colours to be transparent.
Range
Range is a softening value about the tolerance
Notes
•For the Dynamic Keying resource, you can set the chroma values using the dialog above or with the SETTRANSITIONPARAMS external control command.
•Due to compression artefacts, for example in jpg images, what may look like a single colour will be surrounded by similar colours which interfere with this process. Increasing the tolerance can help this problem. It is common when using chroma key images to design specific colours for keying, and selecting an uncompressed format such as TIFF or TGA.
•Uncompressed images such as bmp preserve exact colour perfectly.
Luma Key
This is available for, and sets which monochrome luminance value will become transparent to layers below, and is most usable on monochrome (not multi-coloured), since you pick a greyscale value and tolerance / range around that value.
Luma Value
Choose the value to make transparent.
Tolerance
0 means the exact colour only will be transparent, higher numbers will allow similar colours to be transparent.
Range
Range is a softening value about the tolerance