Absorption refers to how well a paper or material absorbs ink. If the paper is too absorbent, the ink will sink into the fibers and look dull or blurry. If a paper is not absorbent enough, the ink will sit on top and not dry properly, leading to smudging and even ink transfer to other pages.
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%.
