You have your choice of these special effects:
The expression consists of one or more channels, either mnemonic or numeric (e.g. red, 1), separated by certain operation symbols as follows:
<=> exchange two channels (e.g. red<=>blue)
=> copy one channel to another channel (e.g. red=>green)
= assign a constant value to a channel (e.g. red=50%)
, write new image with channels in the specified order (e.g. red, green)
| replace the specified channel in the first image with the specified
channel in the second image (e.g. red | green)
; separate each specified channel to its own image (e.g. red; green;
blue)
For example, to create 3 grayscale images from the red, green, and blue channels of an image, use:
-channel-fx "red; green; blue"
A channel without an operation symbol implies separate (i.e, semicolon).
red; green; blue
1.5 0.0 0.0 0.0, 0.0, -0.157 0.0 1.5 0.0 0.0, 0.0, -0.157 0.0 0.0 1.5 0.0, 0.0, -0.157 0.0 0.0 0.0 1.0, 0.0, 0.0 0.0 0.0 0.0 0.0, 1.0, 0.0 0.0 0.0 0.0 0.0, 0.0, 1.0
1, 2, 1, 2, 4, 2, 1, 2, 1
<amplitude>x<wavelength>
See examples of select ImageMagick Studio effects.