Color fastness to rubbing, also known as crocking fastness, is one of the most fundamental quality indicators for dyed and printed textiles, measuring how resistant a fabric's color is to transferring onto adjacent surfaces under friction. This article explains the principle, test samples, equipment, and step-by-step determination procedures specified in leading international standards such as ISO 105-X12, AATCC 8, GB/T 3920, and JIS L 0849. Understanding these methods helps manufacturers, quality engineers, and buyers accurately evaluate dry and wet crocking performance and prevent dye-transfer failures in real-world use.
Technical Overview
Color fastness to rubbing quantifies the resistance of the color of a dyed, printed, or otherwise colored textile to transfer onto another surface under mechanical rubbing action. In daily use, garments and furnishings constantly rub against skin, linings, accessories, and neighboring fabrics; if dyes are not properly fixed, colored particles or molecules can migrate and stain those surfaces. The test simulates this friction by rubbing a standardized white cotton cloth (the crocking cloth) against the textile specimen under a controlled vertical load and stroke count, then assessing the degree of staining on the white cloth using a grey scale for staining.
The measurement is performed in two modes: dry rubbing, where both the specimen and crocking cloth are conditioned and dry, and wet rubbing, where the crocking cloth is wetted with water to a defined moisture pickup. Wet rubbing is generally the more demanding condition because water swells fibers and mobilizes unfixed dye. Results are reported as grades from 5 (no visible staining) to 1 (severe staining), with half-step ratings permitted. The principal standards governing the method include ISO 105-X12, AATCC Test Method 8, AATCC Test Method 116, GB/T 3920, and JIS L 0849.
Testing Samples
Woven Fabrics
For the reciprocating crockmeter method, a minimum of two specimens are cut, typically not smaller than 50 mm × 140 mm per ISO 105-X12 or 51 mm × 130 mm per AATCC 8. One specimen is oriented with the length direction parallel to the rubbing track and the second with the width direction parallel, because yarn systems and surface structures can influence color transfer. The face side of the fabric is always tested.
Knitted Fabrics
Knitted fabrics are prone to stretching and distortion, so specimens are mounted flat without tension, often on a rigid backing or card, to ensure a stable and uniform test surface. Specimen dimensions follow the same requirements as woven fabrics, and both wale and course directions should be evaluated.
Yarns and Threads
Yarns are wound in parallel wraps onto a suitable rigid holder to form a uniform, flat layer of yarn with consistent density. The holder is then placed on the crockmeter base so the rubbing finger travels across the parallel yarns.
Printed, Raised, and Pile Fabrics
For printed textiles, specimens must be positioned so that each significant color area is rubbed; additional specimens may be required for multicolor prints. For raised, napped, or pile fabrics, ISO 105-X12 specifies the use of a larger 25 mm diameter rubbing finger instead of the standard 16 mm finger to avoid crushing the surface and to obtain a representative result.
Conditioning Requirements
Prior to testing, specimens and crocking cloths are conditioned in a standard atmosphere, typically 20 ± 2 °C and 65 ± 4 % relative humidity per ISO 139, or 21 ± 1 °C and 65 ± 2 % relative humidity for AATCC procedures. Proper conditioning is essential because moisture content strongly affects dye transfer, particularly in wet rubbing tests.
Testing Items
The determination of rubbing color fastness typically includes the following test items and reporting elements:
- Dry rubbing color fastness, using a conditioned dry standard cotton rubbing cloth.
- Wet rubbing color fastness, using a crocking cloth wetted to a specified moisture pickup (100 ± 5 % per ISO/GB, 65 ± 5 % per AATCC).
- Directional testing, with results reported separately for length and width (or warp and weft) directions.
- Staining assessment of each crocking cloth against the grey scale for staining, to the nearest half grade.
- Optional colorimetric evaluation using a spectrophotometer to quantify the degree of staining objectively.
Testing Methods
Reciprocating Crockmeter Method (ISO 105-X12 / GB/T 3920 / AATCC 8)
The standard crockmeter consists of a fixed cylindrical rubbing finger, 16 mm in diameter, that moves in a straight reciprocating line over the specimen. A mass applies a downward force of 9 N, the rubbing track measures 104 ± 3 mm, and the finger completes 10 full to-and-fro strokes within approximately 10 seconds. For the dry test, a dry white cotton crocking cloth (typically 50 mm × 50 mm, complying with ISO 105-F02 or the AATCC crocking cloth specification) is secured over the finger, rubbed against the specimen, and removed for evaluation.
Wet Rubbing Procedure
For the wet test, the crocking cloth is thoroughly wetted with distilled or deionized water and brought to the required moisture pickup by squeezing through blotting paper or a laboratory wringer. ISO 105-X12 and GB/T 3920 specify 100 ± 5 % wet pickup, whereas AATCC 8 specifies 65 ± 5 %, which is one of the most important technical differences between the two systems. After rubbing, the stained cloth is dried in air at a temperature not exceeding 60 °C before grading, and the elapsed time between wetting, rubbing, and drying should be kept consistent and short.
Rotary Crockmeter Method (AATCC 116)
The rotary vertical crockmeter is designed for fabrics with small or limited-area prints where a reciprocating stroke cannot cover the printed motif. A circular rubbing cloth is pressed against the specimen under a standardized load and rotated for a preset number of turns, in either the dry or wet condition. Staining is evaluated in the same manner as the reciprocating method, and results are identified as rotary crocking results because they may differ from straight-line values.
JIS L 0849 Methods
The Japanese standard JIS L 0849 describes two apparatus types: a reciprocating crockmeter (Type I, commonly known as the Gakushin-type tester) that rubs the specimen with a curved friction head over a defined stroke, and a rotary crockmeter (Type II) similar in principle to AATCC 116. Specimens, crocking cloths, and rubbing cycles follow the specific provisions of each apparatus type, so the method used must always be stated when reporting results.
Evaluation of Results
The stained crocking cloths are assessed against the grey scale for staining (ISO 105-A03 or the AATCC equivalent), where grade 5 indicates negligible or no staining and grade 1 indicates severe staining. For multicolor prints, the AATCC Chromatic Transference Scale may be used as an alternative because it accounts for hue transfer rather than depth alone. Assessment should be performed under standardized illumination such as D65 in a color assessment cabinet. Results are reported separately for dry and wet rubbing and for each fabric direction, with any deviation from the standard procedure clearly documented.
Applications
Rubbing color fastness testing is applied extensively across the textile and apparel supply chain for the following purposes:
- Quality control in dyeing and printing mills to verify fixation, washing-off efficiency, and finish performance before shipment.
- Compliance verification against buyer specifications, national labeling regulations, and international trade requirements.
- Product development and optimization of dye recipes, fixing agents, soaping agents, and softeners.
- Failure analysis and root-cause investigation when dye transfer or staining complaints arise from the market.
- Verification testing by accredited third-party laboratories for export documentation and product certification programs.
- Specialty applications such as indigo denim, workwear, automotive upholstery, and home textiles, where friction exposure is high and stringent wet crocking grades are commonly specified.
FAQ
What grade of rubbing fastness is considered acceptable?
While requirements vary by product type and market, most commercial specifications call for grade 4 or higher for dry rubbing and grade 3 or higher (sometimes 3–4) for wet rubbing on fashion apparel and home textiles. Denim and heavily dyed articles often have separate, negotiated limits because indigo and sulfur dyes are naturally less fixed on the fiber surface.
Why is wet rubbing fastness usually lower than dry rubbing fastness?
Water swells cellulosic and protein fibers, opens the fiber structure, and partially dissolves or mobilizes unfixed dye molecules and surface dye particles. As a result, the wet crocking cloth picks up significantly more color during rubbing than a dry cloth, producing a lower staining grade for the same fabric.
How can rubbing fastness be improved?
Effective measures include thorough washing-off of hydrolyzed or unfixed dye after dyeing, optimizing fixation conditions such as alkali, temperature, and time, selecting high-fixation dye classes, applying suitable cationic fixing agents, avoiding excessively deep shades beyond the dye saturation point, and using finishing agents that reduce surface friction without increasing dye migration.
What are the key differences between ISO 105-X12 and AATCC 8?
The main differences are the wet pickup of the crocking cloth (100 ± 5 % for ISO versus 65 ± 5 % for AATCC), specimen dimensions, conditioning atmospheres, the option of a 25 mm finger for raised fabrics in ISO, and the preferred staining assessment scale. Because these parameters affect results, the standard used must always accompany the reported grade.
Can rubbing fastness be measured instrumentally?
Yes. Many accredited third-party laboratories complement visual grey scale grading with spectrophotometric measurement of the stained crocking cloth, converting colorimetric data into an equivalent fastness grade. Instrumental assessment reduces operator variability and is particularly useful for borderline ratings and interlaboratory comparisons.