Värierokaavoja

Värierokaavoja, a Finnish term that translates to "color difference formulas" or "color difference equations," refers to mathematical equations used to quantify the perceptual difference between two colors. These formulas are crucial in fields like color management, printing, textiles, and any industry where precise color reproduction and evaluation are important.

The fundamental principle behind these formulas is to represent colors in a standardized color space, such as CIE XYZ or CIE L*a*b*. Once colors are represented numerically in such a space, their difference can be calculated using various distance metrics. The most widely used and perceptually relevant formula is Delta E (ΔE).

Delta E aims to approximate how a human observer would perceive the difference between two colors. Different versions of Delta E exist, with Delta E*ab (or ΔE*₀₀) being the most recent and generally considered the most accurate in predicting perceptual uniformity across a wide range of color differences. Earlier versions like Delta E* (often referring to ΔE*ab) are simpler but can sometimes underestimate or overestimate perceived differences, particularly for saturated colors.

The output of a color difference formula is a single numerical value. A ΔE of 0 indicates that the two colors are identical. Generally, a ΔE value below 1 is considered imperceptible to the human eye, a value between 1 and 2 is subtly perceptible, and values above 2 are increasingly noticeable. Industry standards often specify acceptable color variation based on these ΔE thresholds.