Rich black.

A black built from cyan, magenta and yellow under the black ink, used on paper so large dark areas print deep instead of the slightly grey solid that black ink alone gives. Gelato specifies 60 60 60 100, a total of 280, for large elements and text in print-ready PDFs. The total is the figure that matters, because every paper and press holds only so much ink, and a black mixed by eye in a design application can run well past it. Shops get it wrong both ways: plain K on a big background prints flat and uneven beside a photo's shadows, and a heavy four-colour mix on small type spreads and picks up coloured fringes when the plates or passes do not line up. On a card or a brochure that shows as a soft black headline on a piece that is otherwise sharp, and the job goes back.