Overview
EN ISO 105‑A06:1997 / ISO 105‑A06:1995 specifies an instrumental colour‑measurement method for determining the 1/1 standard depth of colour of a dyeing on textile materials. It is an accepted colorimetric alternative to the visual assessment described in ISO 105‑A01:1994. The method uses spectrophotometric CIELAB measurements to calculate the lightness required for 1/1 standard depth and compares it with the measured lightness to decide conformity.
Key topics and technical requirements
- Scope: Instrumental determination of 1/1 standard depth (colour depth) for textile dyeings; intended as an alternative to visual matching.
- Measurement system: CIELAB colour coordinates - L* (lightness), C*ab (chroma), and h_ab (hue); measurements using CIE 10° observer and illuminant D65.
- Instrument: Spectrophotometer or colorimeter compliant with CIE definitions (see CIE Publication No. 15.2).
- Specimen preparation: Representative sample mounted on an opaque white backing free from fluorescent whitening agents; recommended minimum size 50 mm × 50 mm; check opacity by comparing L* over black and white backgrounds.
- Calculation: The required lightness for 1/1 depth (kD or hL) is calculated by a formula combining an exponential term and a polynomial P based on hue sectors. Table coefficients (Table 1) and hue limits are used in the calculation.
- Acceptance criterion: The lightness difference ΔL = L* (measured) − L_required must be within ±0.5 (informative Annex B: corrective actions recommended if outside this limit).
- Reporting: Report shall include standard reference (ISO 105‑A06:1995), full sample identification, instrument and geometry, calculated hL, and test date.
Applications and users
- Quality control and laboratory testing in textile mills, dye houses, and independent testing laboratories to verify that a dyeing meets the specified 1/1 standard depth before further colour fastness or matching procedures.
- Production and R&D teams using spectrophotometers for process control, batch comparison, and ensuring reproducible dye concentration.
- Standards and compliance officers who need objective, instrument‑based assessment to supplement or replace visual standard‑depth checks.
Related standards
- ISO 105‑A01:1994 (visual method for 1/1 standard depth)
- CIE Publication No. 15.2:1986 (Colorimetry) - instrument and observer definitions
- EN ISO 105‑A06:1997 is the CEN-adopted version of ISO 105‑A06:1995
Keywords: EN ISO 105‑A06:1997, ISO 105‑A06:1995, colour fastness, 1/1 standard depth, instrumental determination, spectrophotometer, CIELAB, D65, textiles, dyeing, colorimetric method.