Guidelines in setting values

Using Chromakey effects

Guidelines in setting values

Key color

When you're picking the key color, you can use the magnifying glass on the Color Chooser panel to select a color from the Drawing Window. See Using the magnifying glass.

Tolerance

The greater the Tolerance, the more colors are affected. For example:

With a Tolerance of 0%, no colors have their transparency changed - not even the key color.

With a very small Tolerance, such as 5%, only colors very close to the key color have their transparency changed.

With a Tolerance of 100%, all colors have their transparency changed.

You should set the smallest Tolerance you can, to avoid any unwanted changes to colors that are close to your key color. While you're setting the Tolerance, you may find it useful to set the Threshold to 100%; you can then see exactly which colors will be affected.

Note that the default value for the Tolerance is 0% - so if you don't set a value yourself, the node has no effect.

Threshold

The greater the Threshold, the more colors are entirely transparent, and the less the edge of the transparent region is anti-aliased:

With a Threshold of 0%, no colors become entirely transparent - not even the key color.

With a Threshold of 100%, no colors become semi transparent, so the edge of the transparent region has a hard edge.

The default Threshold is 50%, which will make colors close to the key color entirely transparent, but still give a smooth anti-aliased edge. Usually this is a good compromise. However, you may need to change this; for example you might increase the Threshold if the anti-aliased edge is too broad and visible - or if some unwanted colors are still visible, but increasing the Tolerance would remove colors you want to keep.

Using Chromakey effects

Guidelines in setting values

Key color

Tolerance

Threshold