Color Fastness to Rubbing: Principles, Methods, and Testing Procedures

Color fastness to rubbing, also known as crocking fastness, measures a textile's resistance to color transfer when subjected to mechanical friction against another surface. This critical quality parameter is evaluated using internationally recognized standards such as ISO 105-X12, AATCC 8, and GB/T 3920, and serves as an essential acceptance criterion for dyed and printed textiles in global trade. This article explains the testing principles, sample requirements, procedures, and evaluation methods used by accredited third-party laboratories.

Technical Overview

Color fastness to rubbing refers to the ability of a dyed or printed textile to retain its color when rubbed against an adjacent surface, such as a white cotton crock cloth, under controlled conditions. During rubbing, unfixed dyes, pigment particles, or surface-deposited colorants can transfer from the specimen to the adjacent fabric, causing staining that is visually objectionable in end use.

The test is performed on a crockmeter, an instrument that rubs a standardized white cotton fabric against the test specimen at a defined pressure and stroke length for a specified number of cycles. Two conditions are assessed: dry rubbing, which simulates normal abrasion during wear and handling, and wet rubbing, which evaluates color transfer under moisture conditions such as perspiration, rain, or laundering.

Color transfer is quantified by comparing the staining on the white crock cloth against a gray scale for staining, with ratings ranging from grade 1 (severe staining) to grade 5 (no visible staining). Higher grades indicate better fastness performance and a lower risk of color contamination of adjacent garments, upholstery, or skin.

Testing Samples

Woven and Knitted Fabrics

Conventional apparel and home textile fabrics in piece-dyed, yarn-dyed, or union-dyed constructions. Specimens are typically cut into rectangles large enough to cover the rubbing track and are conditioned to standard atmosphere before testing.

Printed and Coated Textiles

Printed fabrics, pigment-dyed goods, and coated or laminated materials are frequently tested because pigment systems that rely on binders rather than chemical fixation are more prone to crocking failure.

Yarns, Embroidery, and Trims

Dyed yarns, embroidery threads, ribbons, labels, and other narrow-fabric components can be assessed by winding or mounting the material onto a suitable carrier so that a representative surface is presented to the rubbing finger.

Leather and Technical Textiles

Leather, coated upholstery, automotive interior textiles, and similar products may be tested using equivalent rubbing fastness methods adapted to the material characteristics and relevant contractual specifications.

Testing Items

• Dry rubbing color fastness: color transfer to a dry white crock cloth under standard rubbing cycles
• Wet rubbing color fastness: color transfer to a wet white crock cloth, typically wetted to 100% water uptake
• Assessment of staining using the gray scale for staining in accordance with ISO 105-A03 or the AATCC chromatic transference scale
• Optional supplementary assessments such as acid or alkaline perspiration rubbing for specific end-use requirements

Testing Methods

ISO 105-X12 / GB/T 3920 Crockmeter Method

The internationally harmonized crockmeter method uses a finger of 16 mm diameter exerting a downward force of 9 N, traversing a 104 mm stroke. The specimen is rubbed for 10 complete strokes within approximately 10 seconds. For the wet test, the crock cloth is wetted with water to a 100% expression, and the stained cloth is dried at room temperature before evaluation. GB/T 3920 is technically equivalent to ISO 105-X12 and is widely applied in markets referencing Chinese national standards.

AATCC Test Method 8

The AATCC crockmeter method follows a similar mechanical principle with a 16 mm finger and a 9 N load. Staining is evaluated using the AATCC chromatic transference scale or the gray scale for staining, and results are reported separately for dry and wet conditions. This method is commonly required for shipments to North American markets.

AATCC Test Method 116 (Rotary Vertical Crockmeter)

For printed patterns with limited areas, small motifs, or fabrics unsuitable for the linear crockmeter, the rotary method rubs a wet or dry crock cloth against the specimen in a controlled rotary motion, allowing accurate assessment of specific printed zones.

JIS L 0849

The Japanese standard covers color fastness to rubbing using both the reciprocating crockmeter and a rotary type apparatus, with conditioning and evaluation procedures aligned to Japanese market requirements.

Evaluation and Reporting

After rubbing, the white crock cloth is conditioned and the degree of staining is graded against the gray scale for staining. The reported result consists of the dry rubbing grade and the wet rubbing grade, each on the 1 to 5 scale, with common commercial acceptance levels typically around grade 4 for dry and grade 3 to 3-4 for wet, depending on the buyer's specification and product class.

Applications

Rubbing fastness determination is applied throughout the textile supply chain for purposes including:

• Incoming quality control of dyed and printed fabrics before garment production
• Verification of compliance with buyer technical packages and product safety specifications
• Product development support when screening dyes, auxiliaries, and fixation processes
• Assessment of aftertreatment effectiveness such as soaping, fixing agents, and binder optimization
• Regulatory and contractual conformity for apparel, home textiles, automotive interiors, and leather goods
• Failure analysis and claims investigation when color transfer complaints arise in the marketplace

Manufacturers, brands, and retailers rely on test reports from accredited third-party laboratories to confirm that products meet the fastness levels appropriate to their intended end use, shade depth, and market region.

FAQ

What is the difference between dry and wet rubbing fastness?

Dry rubbing fastness measures color transfer from a dry specimen to a dry crock cloth and reflects everyday abrasion. Wet rubbing fastness uses a water-wet crock cloth and is generally more demanding because moisture can promote dye bleeding and dissolution of unfixed colorants, so wet grades are typically lower than dry grades for the same material.

Which factors most often cause poor rubbing fastness?

Common causes include inadequate washing-off of hydrolyzed or unfixed dye, excessive dye concentration in deep shades, incomplete pigment binder film formation, unfavorable dye-fiber affinity, and rough fabric surfaces that increase mechanical friction.

How are results graded?

Staining on the crock cloth is compared with the gray scale for staining under standard lighting conditions. Grade 5 means no visible transfer, while grade 1 indicates severe staining. Intermediate half-steps such as 3-4 may be reported when the stain falls between two scale steps.

Are ISO and AATCC results directly comparable?

Although the mechanical principles are similar, differences in apparatus geometry, crock cloth specifications, wetting procedures, and evaluation scales mean that ISO and AATCC results should not be assumed interchangeable. The applicable method should be agreed upon in the purchase contract or product specification.

How can fabric be conditioned before testing?

Specimens and crock cloth are conditioned in a standard atmosphere, typically 20 plus or minus 2 degrees Celsius and 65 plus or minus 4 percent relative humidity, until moisture equilibrium is reached, ensuring reproducible and comparable results between laboratories.