Strange "add" behaviour

[snibgo]

There are many ways of making an image grayscale (ie removing the colours). One is to lower the saturation: "-modulate 100,0,100".

For example:

Code: Select all

convert in.png -modulate 100,0,100 out.png

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convert %1 ( %2 -modulate 100,0,100 ) ( %3 +level 0,80% ) -compose Over -composite %4

[Langschwert]

Thank you again.

convert %1 ( %2 -modulate 100,0,100 ) ( %3 +level 0,80%% ) -compose Over -composite %4

This special command line doesn´t work as intended, it results in a greyscaled camo pattern.

But I changed it a little so it composes a greyscaled image of itself onto the coloured original. It patches "grayscale" instead of camo onto the tank. And that I can paste coloured camo on as usual. It´s not as elegant but it works.

convert %1 ( %1 -modulate 100,0,100 ) %3 -compose Over -composite %4

It seems all that easy when you folks do it. To me it´s all mystery and sorcery.