The black produced in black-and-white printing differs significantly from the black produced in full-color CMYK printing. When creating your design, keep in mind that there are two types of black: standard black and rich black. Standard black uses only black ink (100% K), whereas rich black contains elements of other colors (Cyan, Magenta, Yellow).
While you have both options in design software, you need to know the right print environment.
Standard black is good for keeping text sharp at small point sizes. It is also cost-effective when running a one-color print job. Rich black produces a deeper black tone that is especially good for large, solid areas of black and is used for matching photo backgrounds. But rich black is only cost-effective when you’re already printing four-color process and there is no reversed-out type or small logos. The type tends to plug up since all four colors must line up perfectly when printed. Each black has its own unique purpose.