The amount of ink that is printed on material (paper, cardboard, metal, etc.) is measured by adding the total percentages of each CMYK ink used. As a general rule, if more than 300% coverage is used, it is likely that not all of the ink will be absorbed and smudging will occur.
For example, a black tone with 91% Cyan, 79% Magenta, 62% Yellow and 97% Black is equivalent to 329% coverage. It is strongly recommended to reduce the mix so as not to exceed 300%.
