Delta E is a standard metric for quantifying the difference between two colors. It returns a single numerical value that represents the total magnitude of the color deviation from a target reference. This metric forms the basis for setting objective Tolerance levels in printing.

Delta E is fundamentally calculated within the L*a*b* color space, which is a device-independent model. By converting color data from a device-dependent space (like CMYK) into the perceptual L*a*b* space, Delta E can accurately determine the distance between two color points, thereby translating the complex visual perception of color difference into a simple, manageable number