Overview - ISO 17223:2014 (Plastics - Yellowness Index)
ISO 17223:2014 specifies an instrumental method to determine the yellowness index (YI) and change in yellowness index (ΔYI) for clear, translucent, or opaque plastics. The standard covers common specimen shapes (moulded plaques, discs, films, sheets, powders, pellets) and excludes fluorescent plastics. Measurement and conditioning follow defined laboratory conditions (23 °C / 50 % RH per ISO 291) and use colourimetry based on tristimulus values (XYZ/X10Y10Z10) under CIE standard illuminant D65 or supporting illuminant C.
Key topics and technical requirements
- Measurement methods: Three instrument methods are specified:
- Transmission measurement for sheets, films, plaques, discs.
- Reflection measurement for sheets/films (including use of backing plates when applicable).
- Reflection measurement for pellets and powders (use of a clear specimen container and light trap).
- Optical geometries & integrating sphere: Requirements and acceptable geometries are given (e.g., di:0, de:0, 0:di, 0:de; di:8, de:8; 45a:0, 0:45a). Integrating sphere or equivalent is required when measuring diffusing specimens.
- Calculation: Yellowness index is calculated per ASTM E313 formulae using measured tristimulus values:
- Example (D65, XYZ): YI = 100(1.2985X − 1.1335Z) / Y
- Alternative formulae for different colour systems and illuminants are included.
- Change in YI: ΔYI = YI(after) − YI(before) - positive ΔYI indicates increased yellowness (used to assess ageing, heat/UV effects).
- Sample conditioning & preparation: Statistical sampling, preparation guidance, and measurement environment (ISO 291) are required.
- Precision: Interlaboratory data show generally good repeatability but poorer reproducibility (sensitivity to measurement geometry and inter-lab differences). ISO 5725-2 methods were used for precision assessment.
Applications - who uses ISO 17223:2014
- Quality control and colour stability testing in polymer and plastics manufacturing
- R&D labs assessing ageing, UV/heat exposure, and weathering effects on plastics
- Contract testing and certification labs performing colourimetry and comparative studies
- Material selection for products where visual appearance and long-term yellowness are critical (medical devices, packaging, consumer goods, automotive trim)
- Suppliers specifying acceptance criteria for colour change after environmental exposure
Related standards
- ISO 291 - Standard atmospheres for conditioning and testing
- ASTM E313 - Calculating yellowness and whiteness indices (used for YI formulae)
- CIE 15 - Colorimetry (optical geometries and illuminants)
- ISO 1043-1 - Polymer symbols and abbreviations
- ISO 5725-2 - Repeatability and reproducibility evaluation
Keywords: ISO 17223:2014, yellowness index, change in yellowness index, plastics colourimetry, transmission measurement, reflection measurement, integrating sphere, CIE D65, ASTM E313.