Replacing colors with ImageMagick16 Aug 2013
I’ve run out of black ink on my printer and I had to print one page full of black stuff, the color of the document itself wasn’t important, the content just had to be readable.
I’ve tried to use OSX built-in Quartz filters to change all black pixels to blue, and there’s actually one already called “Blue Tone” but it didn’t work that well for the document (PDF) that I had to print. It couldn’t change the black text and just changed other images and drawings to blue. I’ve even tried to mess up with ColorSync, which is a built-in tool in OSX that allows you to create your own filters.
Tired of that and thinking that it had to be simpler than that, I’ve remembered of the
command-line tool called
convert, which is provided by ImageMagick. I just had to do
one Google search to find how to do it:
$ convert blackish_doc.png -fill blue -opaque black blueish_doc.png
Just had to convert the PDF to PNG before using this line and it saved my life ;)