ISO 14782:2021

Overview

ISO 14782:2021 - Plastics: Determination of haze for transparent materials specifies a standardized laboratory method to measure haze, the optical effect caused by wide-angle scattering of light, in transparent and substantially colourless plastics. The method is designed for haze values below 40% and describes required apparatus, specimen preparation, conditioning, test procedure and how to express results. The standard replaces ISO 14782:1999 and incorporates technical corrections and editorial updates.

Key topics and technical requirements

• Scope and limits: Applicable to transparent, substantially colourless plastics; reliable for haze < 40%. Abraded/matted samples can give underestimated values due to narrow-angle scattering.
• Apparatus: A stabilized light source, optical system producing a parallel beam (≤3° divergence), an integrating sphere with entrance/exit/compensation/photodetector ports, and a photometer. Sphere total port area ≤ 3% of internal reflecting area; recommended sphere diameter ≥ 150 mm.
• Integrating sphere geometry: Entrance and exit ports on same great circle and ~180° apart; exit port subtends ~8° at the entrance; detector positioned ~90° around the sphere; compensation port used to hold measurement efficiency constant.
• Illumination and detector: Spectral output matched to photopic luminous efficiency (V(λ) / CIE y(λ)) per ISO/CIE colorimetry references; detector response linear to within 1% over the measurement range.
• Specimens and conditioning: Clean, defect-free specimens (recommended 50 mm disc or square); three specimens per sample unless specified; condition at (23 ± 2) °C and (50 ± 10) % RH for ≥40 h when required.
• Procedure and results: A defined four-measurement sequence using entrance/exit/compensation ports collects incident, total transmitted and diffuse/scattered signals. Haze is calculated from these measured ratios (the standard contains the precise formula) or equivalently as the ratio of diffuse to total luminous transmittance when appropriate.
• Precision: Interlaboratory trials show reasonable precision up to 40% haze; measurement sensitivity is limited below about 1% haze. Instruments with a compensation port produce more consistent results across labs.

Applications and users

• Who uses it: Plastics manufacturers, quality laboratories, optical component suppliers, R&D teams, and third‑party testing bodies who need standardized optical clarity data for films, sheets, molded parts and transparent polymers.
• Practical uses: Quality control, specification compliance, product development (e.g., packaging, glazing, displays, lenses), material selection and comparison, and supplier acceptance testing.

Related standards

• ISO 13468-1 (total luminous transmittance, single-beam instruments)
• ISO/CIE 11664 series (colorimetry)
• ISO 291 (conditioning atmospheres)
• ISO 472 (plastics vocabulary)
• CIE Publication No. 15

Keywords: ISO 14782:2021, haze measurement, transparent plastics, integrating sphere, total luminous transmittance, diffuse transmittance, optical haze, test method.