1. A method for detecting printing defects, the method comprising: with a physical computing system, creating a matched reference image from a digital image, colors of said matched reference image being closer matched to a scanned image of said digital image; with said physical computing system, determining a color difference between corresponding points on said matched reference image and said scanned image; and with said physical computing system, identifying, points that have said color distance greater than a predefined threshold as potential defects.