Complex image operations using ImageMagick

contrast_mask.sh

#!/bin/bash

convert "$1" \( +clone -colorspace gray -negate -blur 0x300 \) \
        -compose softlight -composite "$2"

highpass_sharpen.sh

#!/bin/bash

# First composite is a grain extract blend.
# Second composite is a grain merge blend.
convert "$1" \( +clone -colorspace gray \( +clone -blur 0x3 \) \
                -compose mathematics -define compose:args='0,-1,1,0.5' -composite \) \
        -compose mathematics -define compose:args='0,1,1,-0.5' -composite "$2"