AATCC 8 Colorfastness to Crocking: Crockmeter

Purpose of Test

The colorfastness to crocking test method measures color transfer of a colored textile to other surfaces by rubbing.

This test method is used for textiles made from various fibers and with various coloring types:

  • Yarn
  • Other Fabrics
  • Dyed
  • Printed
  • Other Coloring Techniques

Terminology Defined

Colorfastness – Colorfastness is a fabric’s ability to retain its color in various conditions.

Crocking – Crocking refers to the rubbing off of color from fabric when subjected to abrasion.

Chromatic Transference Scale – The Chromatic Transference Scale is used to visually measure color transfer or staining during the test. The scale has multiple hues that allow a tester to match a hue from a color transfer test to a numerical score.

Chromatic Transference Scale (Image Source: AATCC)

Gray Scale for Staining – The Gray Scale for Staining is used in colorfastness tests to evaluate staining on undyed textiles. The scale has shades of gray correlated with numbers that allow a tester to match shades with a numerical rating.

AATCC Gray Scale for Staining (Image Source: AATCC)

Instrumental Assessment of Degree of Staining — An alternative to the visual method of evaluating staining.

Test Method

Materials Used for Test

  • White crock test cloth squares
  • Colored test specimen
  • Water
  • Gray Scale for Staining
  • Chromatic Transference Scale
  • Crockmeter
Crockmeter (Image Source: testextextile)

Testing Procedure

Timing of Test – The colorfastness to crocking test may be performed before or after any of the following:

  • Washing 
  • Drycleaning 
  • Shrinkage 
  • Ironing 
  • Finishing
  • Any other relevant cleaning or finishing treatments

Test Procedure (Summary)

Part 1: Rub Test – The textile being tested is mounted on the Crockmeter and rubbed with a white crock test cloth under controlled conditions.

Part 2: Assessment & Grading – The color transfer to the white test cloth is assessed by comparing it with one of the following options: 

  • The Gray Scale for Staining,  
  • The Chromatic Transference Scale, or
  • The Instrumental Assessment of Degree of Staining

A rating is assigned and evaluated against an acceptable quality limit.

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