DELTA E

(ΔE) A term used in color science to express the amount of difference between two colors. “Δ” is the Greek letter used to denote “difference” (usually expressed as the triangle shaped character “Δ”), and “E” is German for “sensation”. ΔE is a single numerical value that essentially averages the difference between two colors. ΔE expresses how far apart two colors are, but not where they are in color space. ΔL*, Δa*, and Δb* are the individual differences for each of the three aspects of color in the L*a*b* color space. ΔL*, ΔC*, and Δh* are the individual differences for each of the three aspects of color in the L*C*h* color space. Overall ΔE L*a*b* is calculated by taking the square root of (ΔL²+Δa²+Δb²). Overall ΔE for L*C*h* colorspace is calculated in the same fashion, and ΔE/ab by taking the square root of (Δa²+Δb²). See also “L*a*b*”, and “L*C*h*”.