Banding is when you see repetitive horizontal bands within the printed image (these may appear as light or dark bands).

This array of colored stripes is designed to check for certain defects with the Printer. It should not be used to check for color consistency or accuracy. The test pattern is printed with the six Printhead colors; Light Cyan, Light Magenta, Yellow, Cyan, Magenta and Black. Each pair of colors is printed by only one Printhead; one is the full color and the other is a lighter shade to help you detect any banding.