The ink coverage or color saturation of a file can be determined by adding the values of the C, M, Y and K colors. For example, yellow in CMYK is represented by 0 C, 0 M, 100 Y and 0 K. If we add up the values, we arrive at a 100% occupancy (0 + 0 + 100 + 0). To form orange, we must add magenta. For example, you get 0 C, 40 M, 100 Y and 0 K. This gives an ink coverage of 140% (0 + 40 + 100 + 0). You can find more information about how to check the ink supply here.
We recommend not to go below 10% for the minimum ink coverage. Lower values can be printed, but these often give a bad result. You also have to take the paper type into account. For example, uncoated paper needs a higher ink coverage because the paper absorbs more ink than coated paper (more information on different paper types). If the ink coverage is too low, the colors may turn out somewhat dull. If the minimum ink coverage deviates from the standard, this will be mentioned in the design guidelines for that product.
Especially light colors (e.g. light yellow, light cyan or light magenta) often have a too low ink coverage.
The maximum ink coverage is in general 300%. Again, don't forget to consider the paper type. For example, we recommend not to exceed 280% when using coated paper. If you exceed the maximum ink coverage, chances are not all the ink will be absorbed by the paper and stains will appear.
Especially dark colors often have a too high ink coverage. This is because you add more K (black) to the CMYK color. To simply get the color black, you can best take 0 C, 0 M, 0 Y and 100 K, which amounts to an ink utilization of 100%. This is recommended for reading texts. For surfaces that need a richer black, you better take a different composition. For more information about the different shades of black, read more here.