Numerical Space
Three-dimensional mathematical models provide a uniform method for representing human color perception across different substrates. The cie l a b color space uses lightness and two chromatic coordinates to define a specific point within the visible spectrum. Mathematical modeling allows a print buyer to specify exact visual requirements.
Visual Boundary
Coordinate transformations convert device-dependent data into these absolute values. Because cie l a b color relies on a standard observer and a specific light source, it isolates the appearance of a package from the inconsistencies of local viewing conditions. Converting measurements from spectral data ensures that a brand color remains consistent when moving from a coated board to an uncoated liner.
Differences between two colors are calculated as delta e values to determine if the result matches the reference.
Process Tolerance
Industrial tolerances define the acceptable deviation from a target value during a production run. While a cie l a b color reading provides the location, the delta e limit sets the boundary for rejection or acceptance. Packaging converters often require tighter tolerances for brand identity elements than for secondary graphics.
Variations in substrate brightness or ink film thickness directly impact the final coordinates recorded by the instrument.
