color - How do I make screenshots look good when printed in CMYK?

When printing screenshots alongside black text, black areas of the screenshot look a washed out "muddy dark grey" and "washed out".

What causes this and can I improve the black color area?

Answer

During the RGB ⇒ CMYK conversion your RGB(0,0,0) values are probably converted to Rich black = CMYK(63,52,51,100) or such; and looks washed out when compared to Plain black = CMYK(0,0,0,100)

Solution is to fine tune the RGB ⇒ CMYK conversion.*

See also: Rich black versus plain black and gd.se question: What is the difference between CMYK and RGB?

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*) To maximize black (= K = Key) in Photoshop: Edit → Convert to profile → Custom CMYK... → Black Generation: Maximum

But this and other settings should, of course be set according to your media and printer.