Rubbing and crocking fastness testing
Rubbing fastness, also called crocking, measures how much colour a dyed fabric transfers onto another surface when the two are rubbed together. It is a test of surface colour rather than of the dye inside the fibre, which is why a fabric can hold an excellent washing rating and still crock: the dye that has not penetrated or has migrated to the surface is the dye that transfers. Rubbing is assessed twice on every sample, once dry and once wet, and the wet result is usually the lower of the two.
What rubbing fastness measures
The property decides whether a shade is usable before it decides whether it is attractive. Deep shades, certain colour chemistries and heavily finished fabrics are the ones that fail it. For a garment maker the risk is a shade that marks a lining, a seat or another garment in transit; for an upholstery or automotive buyer it is a rub-off that shows on a light surface. Rubbing fastness is therefore specified on the order alongside washing fastness rather than instead of it.
The reference Nuchem follows
Nuchem runs the rubbing test to ISO 105-X12:2016, covering dry and wet rubbing on dyed cotton. The crockmeter is the instrument that produces the movement, and its geometry and force are fixed by the method so that results from different laboratories can be compared.
| Condition | Setting |
|---|---|
| Finger diameter | 16 ± 0.1 mm |
| Applied force | 9 ± 0.2 N |
| Stroke length | 104 ± 3 mm |
| Rubbing cloth | ISO 105-F09 cotton, 50 ± 2 mm per side |
| Conditioning | At least 4 hours at 20 ± 2 °C, 65 ± 4 % RH |
| Cycles | 10 complete forward and back cycles, 1 cycle per second |
| Staining graded by | ISO 105-A03 grey scale |
How the test is run
Four specimens are cut, warp and weft for each of the dry and wet tests, and both the specimens and the rubbing cloths are conditioned separately before testing begins. The dry and wet methods then differ only in the state of the rubbing cloth.
- Specimens of at least 50 mm × 140 mm are cut for warp and weft.
- Specimens and rubbing cloths are conditioned for at least four hours at 20 ± 2 °C and 65 ± 4 % relative humidity, and are tested in that atmosphere.
- Dry rubbing: the specimen is clamped over non-slip abrasive paper and a fresh cloth is fitted with its weave parallel to the direction of rubbing, then ten complete forward and back cycles are run at one cycle per second and repeated for the other direction.
- Wet rubbing: the conditioned cloth is weighed, soaked in distilled water and adjusted to 95-100 % pickup, then the dry-test rubbing is repeated promptly on fresh specimens using fresh wet cloths, and the cloths are air-dried.
- The rubbed cloths are reconditioned for at least four hours and loose fibres are removed.
- Each cloth is backed with three white rubbing-cloth layers and the staining is graded under standard assessment lighting.
How the result is read
Staining is graded on the grey scale to ISO 105-A03, in half grades from 1 to 5, where 5 is no perceptible staining of the rubbing cloth. Four figures are produced from one sample: dry warp, dry weft, wet warp and wet weft. Recording all four matters, because a fabric can pass in one direction and fail in the other, and the wet figure is normally the one a buyer will hold the order to.
The values agreed for each published COTFIX grade are listed on the fastness and solubility data page. The method sheet records the sample identity, the pickup, the conditioning and test atmosphere, the duration, and the finger and force settings, so that a figure can be traced back to the conditions that produced it.
Frequently asked questions
Washing fastness measures what happens to the dye inside the fibre when the fabric is laundered. Rubbing fastness measures how much colour transfers from the surface by mechanical contact. A fabric can perform well in one and poorly in the other.
Water softens the fibre surface and mobilises dye that has not fully fixed or has migrated to the surface, so more colour transfers onto the rubbing cloth. That is why the wet figures are the ones most orders specify.
It draws a standardised piece of white cotton cloth back and forth across the specimen under a fixed load and finger geometry, so the rubbing is repeatable rather than a matter of how hard an operator presses.
A half grade of staining under the conditions of the test, read on the ISO 105-A03 grey scale, where 5 is no perceptible staining and 1 is severe. It is a comparative measure, not a statement that no colour can ever transfer.
Yes, in both the dry and the wet test, so four figures are reported for each sample.
Need a crocking figure for a deep or difficult shade?
Give the COTFIX grade, the substrate and the finishing the fabric receives, and the laboratory will run the dry and wet rubbing tests and report warp and weft separately.