ASTM D6961/D6961M-09 (2021) PDF

Full title and description

St ASTM D6961/D6961M-09 (Reapproved 2021) — Standard Test Method for Color Measurement of Flax Fiber. Provides procedures for instrumental (spectrophotometric) measurement and reporting of the color of flax (bast) fiber using CIE-based colorimetry and common reporting metrics (for example CIELAB L*, a*, b* values and related color-difference calculations).

Abstract

This standard describes an instrumental method for measuring the color of flax fiber specimens using spectrophotometers and established CIE colorimetry practice. It defines specimen presentation, measurement aperture considerations, data reduction to CIELAB coordinates, use of CIE standard observers and illuminants, and guidance on interlaboratory comparison and statistical bias. Units in SI and inch‑pound systems are provided and treated independently.

General information

• Status: Current edition — D6961/D6961M − 09 (Reapproved 2021).
• Publication date: Approved July 1, 2021 (published July 2021; original adoption 2003 with earlier revisions).
• Publisher: ASTM International.
• ICS / categories: 59.060.10 (Natural fibres); Textiles / Colorimetry.
• Edition / version: D6961/D6961M − 09 (Reapproved 2021).
• Number of pages: 3 pages.

Scope

The standard covers instrumental color measurement of flax fiber. It specifies how to present fiber specimens to a color spectrophotometer, which observer and illuminant conventions to use, and how to calculate and report colorimetric values (CIELAB L*, a*, b* and derived differences). The document treats SI and inch‑pound units as separate systems and includes guidance for statistical interlaboratory comparisons and for relating measurement practice to textile conditioning requirements.

Key topics and requirements

• Specimen preparation and presentation for spectrophotometric measurement (compact aperture, window usage to protect instrument and average fiber variation).
• Use of CIE standard observer and standard illuminants; conversion of spectral data to tristimulus values and then to CIELAB L*, a*, b*.
• Recommended instrument aperture size and procedures to average natural color variation in flax.
• Reporting formats — L*, a*, b* coordinates and color-difference calculations (ΔE) consistent with established colorimetry practice.
• Instructions that SI and inch‑pound values are to be used independently (do not combine systems).
• Guidance on interlaboratory comparison, statistical tests for bias, and corrective actions when bias is found.
• References to related conditioning and terminology standards affecting test reproducibility.

Typical use and users

Used by textile testing laboratories, flax growers and processors, fiber merchants, quality control teams in textile and composite supply chains, research laboratories studying bast fibers, and standards/conformity bodies. Typical applications include acceptance testing, QA/QC of processed flax fiber, material specification, and research comparing processing effects on fiber color.

Related standards

Commonly used together with ASTM D1776/D1776M (conditioning and testing textiles), ASTM E308 (practice for computing colorimetric data from spectral data / CIE procedures), ASTM D6798 (terminology relating to flax and linen), AATCC Evaluation Procedure 6 (instrumental color measurement procedures), and other D13 subcommittee documents on flax (for example D7025, D7076 where relevant).

Keywords

flax fiber, color measurement, colorimetry, spectrophotometer, CIELAB, L* a* b*, ΔE, textile testing, bast fibers, ASTM D6961, D13.17.

FAQ

Q: What is this standard?

A: ASTM D6961/D6961M-09 (Reapproved 2021) is a short test method that defines how to measure and report the instrumental color of flax fiber using spectrophotometric and CIE colorimetric procedures.

Q: What does it cover?

A: It covers specimen presentation, measurement with a color spectrophotometer, conversion of spectral data to tristimulus and CIELAB values, reporting conventions, unit system handling, and basic interlaboratory comparison guidance.

Q: Who typically uses it?

A: Textile and fiber testing laboratories, flax processors and merchants, quality assurance personnel in textile and composite industries, and researchers working with flax and linen fibers.

Q: Is it current or superseded?

A: The designation used here is D6961/D6961M − 09 with reapproval in 2021 (the edition is listed as Reapproved 2021). Users should confirm whether a later reapproval or revision exists before relying on the standard for compliance or procurement decisions.

Q: Is it part of a series?

A: It is part of ASTM Committee D13 (Textiles) outputs and is maintained by Subcommittee D13.17 (Bast Fibers and Plants). It is commonly used alongside other D13/D13.17 standards for flax (terminology, conditioning, and other test methods).

Q: What are the key keywords?

A: Flax fiber, color measurement, CIELAB, spectrophotometer, colorimetry, ΔE, textile testing, D13.17.