What can I do with this online tool?

You can convert a PDF from RGB to CMYK. Documents made with Word, LibreOffice, a browser or most other programs use RGB colors, the colors of screens (red, green and blue light). Printing uses CMYK, the four inks cyan, magenta, yellow and black. Print shops often expect a print-ready PDF in CMYK. Professional tools like Adobe Acrobat Pro can convert a PDF to CMYK; this free service does it too.

How is my PDF converted?

• All colors: text, vector graphics (lines, areas, logos) and images are converted from RGB to CMYK with the ICC profile you choose. Pages, text and image resolution stay as they are.
• Like professional tools: colors are mapped with "relative colorimetric" and black point compensation, the default of Photoshop and Acrobat and what print shops expect: colors the inks can print stay as they are, dark tones keep their detail.
• Pure black: black and gray text and graphics are printed with black ink only (K), not with all four inks. Small text stays sharp even if the printing plates are slightly off, and the paper gets less ink. Images keep the profile's conversion. You can switch this off below the profile.
• Preview: the result shows page 1 before and after, as it will be printed, and tells you if colors had to be adjusted because CMYK inks can't print them.
• Privacy: your PDF and the result are deleted automatically after 20 minutes.

My print shop has problems with the PDF?

Please let us know! Send us the PDF you uploaded, the CMYK PDF you got from us and what your print shop said (see Contact). We test it and improve the conversion.

What are these profiles and which should I use?

There are many kinds of paper: newsprint, glossy paper for magazines, uncoated and coated paper for brochures. Each takes ink differently: newsprint soaks up more ink than glossy paper. If this isn't taken into account, images get too dark and the ink blurs. An ICC profile describes how colors print on a specific kind of paper and press.

Best ask your print shop which profile to use. If you can't: GRACoL 2013 is the current standard in the US. In Europe, it's PSO Coated v3 for coated and PSO Uncoated v3 for uncoated paper; many print shops still use their predecessor ISO Coated v2 (300%) ECI.

When I convert RGB to CMYK, the colors change?

Some RGB colors that you can see on your monitor (in particular blue, green and all bright, vibrant colors) cannot be printed with standard CMYK inks. They are converted to the closest printable colors.

Can I also convert images?

Yes, with our sister website www.rgb2cmyk.org, which converts images (JPG, PNG, TIFF, GIF) from RGB to CMYK.