CMYK is the colour mode required for all professional print production. If your PDF uses RGB, converting it to CMYK before printing is essential for accurate colour reproduction. This guide explains how to do it correctly.
Why CMYK Conversion Matters
Printing presses use four inks — Cyan, Magenta, Yellow and Black (CMYK). Screens display colour using light (RGB). The two systems have different colour ranges. When a printer converts RGB automatically, vivid colours often become duller or shift in hue. Converting yourself gives you control over the result.
Choosing the Right ICC Profile
A professional CMYK conversion uses an ICC colour profile to map RGB values accurately. Common profiles:
- ISO Coated v2 (ECI) — standard for European coated paper (magazines, brochures, flyers)
- ISO Uncoated — for uncoated paper (letterheads, some brochures)
- FOGRA39 — widely used in European offset printing
- GRACoL / SWOP — US print standards
Ask your print shop which profile they require if unsure.
Convert in Design Software
If you have the original design file, this is the preferred approach:
- Photoshop — Edit → Convert to Profile → select CMYK profile
- Illustrator — File → Document Colour Mode → CMYK
- InDesign — set CMYK in Document Setup, export with PDF/X preset
Convert Automatically from a PDF
If you only have the PDF, PrintConvert247 converts it to CMYK automatically using ISO Coated v2 — the professional standard for European print.
Convert your PDF to CMYK — automatically
Upload your file and get a CMYK print-ready PDF in seconds. Free to try.
Convert to CMYK →Verify After Converting
After conversion, check the result with PrintReady247 to confirm the file is fully CMYK with no remaining RGB elements before sending to the print shop.