Blue Color In Your Artwork
When you use blue in your artwork, always make sure to leave at least 30% difference in your Cyan and Magenta values.
100% C 100% M 0% Y 0% K
Blue is very close to purple in the CMYK spectrum.
It is the best way
use a low amount of magenta, whenever you use a high amounts of cyan, to avoid purple.
EXAMPLE: C-100 M-70 Y-0 K-0