colorhold

Remove all color information for all RGB colors except for certain one.

The filter accepts the following options:

'color'

The color which will not be replaced with neutral gray.

'similarity'

Similarity percentage with the above color. 0.01 matches only the exact key color, while 1.0 matches everything.

'blend'

Blend percentage. 0.0 makes pixels fully gray. Higher values result in more preserved color.