How to export black as K-black instead of CMYK-black in PDFs?

• May 6, 2024 - 21:25


I see that the PDFs exported from Musescore are all full-colour.

I wanted to export the file so that black would be printed with black ink and not with CMYK: at this moment the printer prints all black in full colour even if it is a black and white pdf.

How can I achieve this?


If you have a pdf in "full colour", why don't
you just print it in greyscale or in black and white. At least my printer has this option.

In reply to by TomStrand

Yeah, File / Print and Print in grayscale (black and white) is roughly center, in the second row of settings, directly below the Properties and Advanced buttons on the Print dialog of my (most current) version of Adobe Acrobat Reader. Depending on what printer you have it might be in other places. If it's not there, the second place to look would probably be under the Properties or Advanced buttons.

In reply to by TheHutch

Yeah, that of course would do, but I am using the pdfs in a desktop publishing workflow with Scribus. And there I find that all the black (text, staff, notes etc) made with Musescore is CMYK black, while the black made with Scribus is 100% K black. In a full colour workflow this makes a difference, because the blacks print and look differently.

Hence the previous question: is CMYK black output in PDFs expected behaviour?

As far as i know, the pdf standard is open in the sense the user (e.g. MuseScore) defines how black is printed/generated. The ISO standard that specified the PDF format (Portable Document Format) is ISO 32000 defining the document in a manner independent of the application software, hardware, and operating system including specifications for color spaces.

MuseScore uses the built-in PDF writer available in most operating systems, such as PDF printer on Windows or Quartz PDF on macOS. When you export a score as a PDF in MuseScore, it generates the PDF using the system's default PDF writer.

When printing in black using a PDF printer, black is typically a combination of cyan, magenta, yellow, and black (CMYK) "ink" in varying proportions to create different shades of gray and ultimately black. I think, if you need a pure black C(0%) M(0%) Y(0%) K(100%); maybe, you can set this by default in the default OS pdf printer. I'm not at the computer just now, so I cannot check.
If not, it might be possible to check in the MuseScore code how black is defined in the print command to the pdf printer.

However, is pure black really desirable as it creates very sharp borders between the black and the white and this can be tiresome for the eye and loose the focus? I'm normally working in space engineering and optical sensor optimisation. If you have extended stellar objects, e.g. a star, which extend more then a pixel, you have an uncertainty where the center of the star is. For this reason, we defocus the image to get it "blurred", i.e a kind of greyscale image of stars for which a simple Gaussian distribution processing then can be used to find the centre of an extended object/star with sub-pixel accuracy.

In reply to by underquark

If you have Acrobat Pro, you can check the color scheme used for any point of the document in the so called preflight mode.
Before retirement I used to have Acrobat Pro though my work. Now as retiree, I feel Acrobat Pro is too expensive so I've changed to Kofax Power PDF which has more of less the same functions as Acrobat. However I've not checked if there is a preflight mode but the are probably others as well. You can import PDFs in Gimp (, an image processing program. Maybe this can used. Otherwise, Google is your friend or, why not, Chat GPT.

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