Delta E is a unit of measurement for color difference perceived by humans. The E stands for Empfindung; German for “sensation”. The scale goes from 0 to 100 with 0 meaning no color difference and 100 being the greatest color difference possible. Delta E has evolved quite a bit over the last four decades. It started as a simple mathematical calculation to later a calculation that incorporates adjustments to account for variations in a human’s ability to perceive color differences in different color regions. In the most modern delta E standards (delta E CMC, 2000), a delta E of less than 1.0 is not perceivable by most humans. People who either have superior color vision or have received specific training can perceive color differences down to 0.6 delta E.