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Created January 15, 2022 10:27
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imagemagic-negate.md

ImageMagic Color Invert

ImageMagick 6

Can invert color intensities with -negate option only)

-negate

convert input.png -negate output.png

ImageMagick 7

Requires the -channel option with -negate)

Changed Options

convert input.png -channel RGB -negate output.png

This is because the default active channels contain transparency_(opaque/alpha)_ in ImageMagick 7.x

ImageMagick6: DefaultChannels = ((AllChannels | SyncChannels) &~ OpacityChannel)
ImageMagick7: DefaultChannels = AllChannels

Most algorithms update the red, green, blue, black (for CMYK), and alpha channels. Usability of -negate seems to be sacrificed for overall consistency.

More detail for you

source

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