EN ISO/CIE 11664-4:2019 PDF

Overview

EN ISO/CIE 11664-4:2019 (Colorimetry - Part 4) defines the CIE 1976 Lab* colour space (commonly called CIELAB) and the procedures for calculating its coordinates from tristimulus values. The standard specifies correlates of lightness (L*), chroma (C*), and hue (h*), and provides two methods to compute Euclidean distances in CIELAB to represent perceived colour differences (ΔE*ab). Annex A gives the reverse transformation back to tristimulus values. This is the 2019 ISO/CIE/CEN version that supersedes the 2011 edition.

Key topics and requirements

• Defines the mapping from tristimulus values (X, Y, Z) to L*, a*, b* in a three‑dimensional, approximately uniform colour space.
• Covers calculation of correlates: lightness, chroma and hue derived from L*, a*, b*.
• Specifies two Euclidean distance methods in CIELAB to quantify perceived colour differences.
• Applies to tristimulus values calculated with CIE 1931 (2°) or CIE 1964 (10°) standard colorimetric observers:
  • Use CIE 1931 when the stimulus subtends about 1°–4° at the eye.
  • Use CIE 1964 when the angular subtense is greater than ~4°.
• Requires consistent use of the same colour‑matching functions and specified white stimulus for all compared samples.
• Applies to reflecting and transmitting object colours; excludes areas that appear to be self‑emitting or specularly reflecting primary light sources (unless self‑luminous displays are normalized to simulate objects).
• Includes guidance on normalization (e.g., Y = 100 for 100% reflectance/transmittance) and notes on measurement methods (spectrophotometry vs tristimulus colorimeters).
• Annex A: reverse transformation from CIELAB to tristimulus values.

Applications

• Quality control and pass/fail tolerancing in paints, coatings, textiles, plastics, printing and packaging.
• Colour specification and matching workflows in industrial manufacturing, design and branding.
• Colour difference evaluation in imaging, photography, display calibration, and colour metrology laboratories.
• Basis for further colour‑difference modelling and communication between suppliers, manufacturers and clients.

Who should use this standard

• Colour scientists and engineers, metrologists, product and quality managers, standards committees, test laboratories, and display and materials manufacturers who need a standardized, reproducible method to compute CIELAB coordinates and basic ΔE*ab values.

Related standards

• ISO/CIE 11664‑1 (CIE Standard Colorimetric Observers)
• CIE S 017 (International Lighting Vocabulary)
• Note: This part does not cover advanced colour‑difference formulae (CMC, CIE94, DIN99, CIEDE2000), which are addressed elsewhere.

Keywords: CIE 1976 Lab*, CIELAB, colorimetry, colour space, colour difference ΔE, tristimulus values, CIE 1931, CIE 1964, colour measurement, ISO/CIE 11664-4.