http://www.graphic-design-employment.com/4-color-process.html

1.Look at a full color magazine through a magnifier -- all the cocors are made up of CMYK(cyon,magenta,yellow,keyline)patterns

2.Look at an area of spot color through a magnifier, there is no screen, it shows an area of solid,unbroken color

Full color 四色印刷，4 color process printing

Spot color 专色印刷

网点：screen