The presses we have here has no issue with printing black. We run into prolbems sometimes when our chemical and plates are not so good.
If you want a rich black i suggest that you use C100 M100 Y100 K100.
Can't get darker than that.
It also depends on the press and pressman....he gotta get perfect registration.
There's another tip: some printing bureaus when they want to make a black in all its fullness, apply a pad (under black) about 30% Cyan . (offset printing system)
so far i've heard of many different rich black combinations. the key is to saturate cmyk blacks just far enough without getting to much of an ink build. 100% across the board is heavy. 60, 40, 40, 100 sounds like it's pushing it enough.
Adrian Juman said:If you want a rich black i suggest that you use C100 M100 Y100 K100.
C100 M100 Y100 K100 is too much, and causes problem to the printer. Too much tint is slow to dry and cause many problems on the printing process. The maximun percentage must be 320% but the best results is with 240% / 280% (for example 60+40+40+100 as suggested Rodrigo). Really a 40% of cyan is enough, but causes a "blue" tone. And using the same values of yan, magenta and yellow causes a "brown" tone. For this reason, is better to use a little more cyan than other tints