915cfcdb9ff75c271d3144b6df91a80dfef498ae
2 convert
$< -set colorspace Gray
-separate
-average
$@
4 convert
$< -set colorspace Gray
-separate
-average
$@
8 -sProcessColorModel
=DeviceGray \
9 -sColorConversionStrategy
=Gray \
11 -dCompatibilityLevel
=1.5 \