AATCC revises widely-used gray scale evaluation procedures

The revised standards clarify the term ‘grade’ as a noun. Specimens are assigned a grade based on comparison with the gray scale. ‘Evaluate’ is the action of assigning a grade, said AATCC in a press release.

Half-step grades are now designated by decimals. While the dash form (e.g, 2-3) is still acceptable, the decimal (e.g, 2.5) is preferred. The decimal format simplifies data entry and statistical analysis.

Appendix A of the revised standards include an experimentally-verified procedure for determining if scales are within tolerance. The procedure specifies exact parameters for measuring the gray chips on a spectrophotometer. If all chips are within the stated tolerances, the scale may be used. For those who choose not to use this procedure, a one-year replacement interval is recommended.

One of the most visible changes to the standards is the addition and update of figures. General images of the scales now show the decimal half-step designations. Additional figures show the proper arrangement of clearly-labelled specimens, scale, and mask. AATCC EP2 includes three such photos to clarify use for general, crocking, and multifibre evaluation. (PC)

ALCHEMPro News Desk – India