It is not actually a different color but a different configuration of dots within the pattern. If you picture the form with a grid underneath, the Anoto pattern is really just dots printed with a specific offset from the grid. The digital pen “sees” a portion of the pattern with the infrared camera and that portion tells the pen the pattern address as well as the X,Y coordinates of the ink stroke on the form. Printing different patterns on each form page is done to ensure Mi-Forms knows how to apply the ink to each page of each instance of a form appropriately. If all pages were the same pattern, we would not be able to determine where one form page ends and another begins.
Posted in: Digital Pens