Glossary → Delta E
Delta E.
a single number for the distance between two colors
One number for how far apart two color samples are, the lower the closer, calculated by more than one formula (delta E76, delta E94, delta E2000), so a stated tolerance means nothing until someone says which. An ICC profile gets a print near the target color; Delta E is the measurement that proves it landed inside what the client agreed to. It replaces an argument held under production-floor lighting with a reading.