Few standards exist to objectively judge flax quality. Color is an important factor in the quality of flax fiber. Natural variations in raw flax fiber, various processing steps, fiber blending, and a wide range of end uses contribute to the need for a standard method of objectively measuring the color of flax fiber. Spectrophotometic data provide an accurate, precise determination of the color of flax fiber. Colorimetric data are obtained through specimen measurement by combining specimen spectral data with data representing a CIE standard observer and a CIE standard illuminant, as described in Method E 308.

If there are differences of practical significance between reported test results for two (or more) laboratories, comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, use the samples for such a comparative test that are as homogeneous as possible, drawn from the same lot of material as the samples that resulted in disparate results during initial testing and randomly assigned in equal numbers to each laboratory. The results from the laboratories involved should be compared using a statistical test for unpaired data, a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results for that fiber sample type must be adjusted in consideration of the known bias.