A book I'm working on (heavy with photographs) which will be output in CMYK, has a lot of black backgrounds, should I use just a standard defined black (K=100, C,M+Y=0), or will that be a bit grey on a final print run - would it better to define a solid black colour with a set amount of Cyan for any large chunks of black backgrounds? TIA!

100% k is usually fine, but for a nice deep black, I usually run a 40% cyan shiner, so 100% k and 40% c.

Watch out if the black touches the black background of the photos though, as this will be an even richer black and you'll see a line where the photo ends. Hope that makes sense!

Thanks Tom will give it a go, all the images have a white keyline, so hopefully will be ok!

You'll have to hope the printer can line the plates up properly then. That's the only problem with printing black made up of a number of colours.

Is there a rich Pantone black you cold use instead? Ask your printer for guidance on this.

If the printer is using computer to plate (which any decent printer will be) registration shouldn't be a problem, but paul's right, it's always worth asking them for guidance.

It's definitely CTP, direct from the press-ready PDF with their PDF settings I'll create, but will check anyway. Thanks

Checked and am using a rich black composed of 60C, 50M, 50Y and 100K. Fingers crossed...

Hmm, that's quite a dense ink coverage, I'd be crossing more than just my fingers!


I'd definitely insist on seeing a proof first, or a visit to the printers for a print pass. You may have to weight up that keyline slightly to compensate for any registration problems or ink spread. For example, a 1pt white keyline might end up looking like a 0.5pt keyline (or less) if the ink spreads a little into it. It's always worth asking your printers and see if they can suggest alternative process splits - or maybe a spot-UV will give you that richness in the blacks?