Convert rich black to CMY=0 K=100

I’m printing some business cards, and the print shop won’t print rich black . They want everything at CYM=0 and K=100 (it’s cheaper for them). So now I have to change my pdf’s rich black into just K=100.

The thing is, the pdf is a mix of jpegs and vector images, so it’s not just a case of selecting objects and changing the colour values.

In Adobe Illustrator CS4, here’s the quick and easy solution:

Select all > Edit > Edit colours > Convert to Greyscale


Select all > Edit > Edit colours > Convert to CMYK

That’s it. If you open the file again in illustrator or photoshop, you’ll see that everything is now CMY=0 plus some value of K, 0 – 100.


  1. Print houses don’t want rich black with fine line items (like type) because the 4 CMYK plates have to be lined up exactly for it not to look blurry on the print. Paper stretches and moves in the print process, and it is fairly impossible to line up all 4 plates to razor sharp accuracy. If your design is all-black anyway, they will take the grayscale image, no need to convert back to CMYK. Just never pick rich black for type and fine lines if your image has color in it.

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