Dickeson--Cyan, Yellow, Magenta, Black Magic

"You see, Roger, the scanner software programs find the color bars you lay on that 11x17˝ glass bed wherever they are and however they're displayed," the rep said.

"How wide do those color bars have to be?" I asked.

"Width doesn't matter," the rep replied. "Quarter of an inch, eighth, 16th, 32nd, whatever you want. You print 'em, and the scanner finds 'em and measures 'em."