How to Change a PDF to CMYK for Printers. The colors you see in a PDF file on your screen don't always translate precisely to the shades that appear when the document comes out of your printer ...

Cyan’s plugin is a color emulator that lets you convert the colors in your file from RGB to CMYK for printing or from CMYK to RGB if editing for a screen-based result.

Despite this shortcoming, GIMP can convert CMYK images to RGB when it opens them and if you save these images to press-ready PDFs, GIMP will convert them back to CMYK when it saves them.

The open source image editing app GIMP has released version 3.1.2. GIMP 3.1.2 is the first development release for GIMP 3.2, and includes new paint modes, text options, CMYK settings for printing ...

If you can’t create the design in CMYK from the beginning, you should use software that converts RGB to CMYK — although this often results in disappointing color differences.