Rich Black Tips, Information, and Formulae

For large fields of black, we usually use 60C 40M 40Y 100K. 

I make sure to check the rich black formula in any project I am revising, because there are many files in our archives in which the rich blacks were set to 100/100/100/100

@Pariah - What do you recommend / use for Rich Black?

In addition to the good info above, some digital presses show 100% black nicely and adding extra ink makes little or no difference. For offset, you do not want to exceed the maximum ink density for the particular printing conditions, you never want to use 100% of all colors (AKA registration). A gloss aqueous or UV coating can add extra depth to blacks.

If registration could be an issue, you do not want to use a rich black on small type or other thin black elements, as you may see a color shift if it's printed out of registration.

I like 30,0,0,100 or 30,30,30,100.

As Monika says there are a lot of variables and the printer may change them. They can also change when you make a PDF, if with Colour Management on, you are set to convert.

As someone in the pre-press trade since 1987 though (no Macs and Adobe used back then for most), a good place to start may be:

100K 50C

or

100K 50C 30M 30Y (for a richer black)

It all can depend on what substrate you are printing on, the coverage area of the black and the look you are trying to achieve.

This needs to be checked with the printing service. After all it depends on the process and the paper how much ink to add. Some printers might even throw out your added inks automatically in their preprinting process.

So you really better contact them and read the specifications (when it's an online printing service) very carefully.

I had to smile... after watching Survivor on TV, my first thought was a Black Tipped Shark swimming near the beach