Guide · For the trade
Crocking, bleeding and lightfastness: how to read carpet colorfastness on a spec sheet
Crocking is color rubbing off a carpet or rug onto whatever touches it: a sock, a white linen skirt, a damp cloth. It is tested with AATCC 8 (a crockmeter rubs a white cloth across the pile, dry and then wet) and graded 1 to 5, where 5 is no transfer; a residential spec should read 4 or better dry and 3 or better wet. Colorfastness to light is a separate test, AATCC 16, also graded 1 to 5 after 40 or 80 hours of xenon light, and 4 is the number to look for.
This guide is for the designer or the junior reading a spec sheet before a submittal, or answering a client who found a pink smudge on a white sofa skirt. It covers what crocking means, how it differs from bleeding and fading, which fibers carry the risk, the numbers to ask for, and what to tell the cleaner.
What does crocking mean?
Crocking is dye that was never fully fixed to the fiber coming off under friction. Every dyed textile has some loose surface dye; crocking is when there is enough of it to mark a second surface. Dry crocking shows up as a tint on light socks and the underside of upholstered skirts. Wet crocking is worse, because moisture carries the loose dye, so it shows up after a spill or a spot clean. Dark and saturated colors crock most: indigo, deep red, black and anything over-dyed to get there.
Crocking, bleeding and fading are three different failures
The spec sheet treats them separately, and so should the conversation with the client.
| Failure | What the client sees | Cause | Test and scale |
|---|---|---|---|
| Crocking | Color on socks, hems, cushions | Loose surface dye, friction | AATCC 8, Gray Scale for staining, 1 to 5 |
| Bleeding | Dark dye migrating into light areas when wet | Water-soluble dye, excess dye, wrong cleaning chemistry | AATCC 107 colorfastness to water, 1 to 5 |
| Fading | Lighter color at the window side, under a skylight | UV light, ozone, gas fumes | AATCC 16 lightfastness, 1 to 5; Blue Wool ISO 105-B02, 1 to 8 |
On the AATCC scales 5 is unchanged and 1 is severe. On the Blue Wool scale, which European mills use, 8 is best; a wool Wilton rated 7 out of 8 is in the top class. A carpet can be excellent on one test and poor on another: a printed polyester can pass crocking and still fade at a south window.
Which fibers and dye methods carry the risk
Solution dyed nylon and solution dyed polypropylene have the pigment inside the fiber, so there is nothing on the surface to rub off; they are the safe answer where crocking or bleeding would be unacceptable, and the solution dyed nylon guide covers how to confirm it on the sheet. Piece dyed and skein dyed wool is very good when the mill has washed the yarn properly; the reputable wool mills in our library rate 4 and above dry. Hand-knotted and hand-loomed rugs are the ones to test, because small dye houses vary; a deep red or black ground should always get the damp white cloth test before it ships. Viscose and bamboo silk hold dye poorly when wet, one more reason they belong only in dry, low-traffic rooms. Cotton and jute crock more than wool at the same depth of shade.
The numbers to ask the mill for
For residential broadloom, ask for crocking (AATCC 8) dry 4 or better and wet 3 or better, and lightfastness (AATCC 16) 4 or better at 40 hours. For hospitality and healthcare, the same crocking numbers with lightfastness at 80 hours, plus colorfastness to ozone (AATCC 129) and to burnt gas fumes (AATCC 23) in humid or urban sites. Masland publishes colorfastness of 4.0 or better on its sell sheets, so the junior can pull the number without a call. For a custom rug, ask for the dye lot's colorfastness certificate, or request a strike-off and test it yourself.
How to test a sample in the showroom or the studio
- Rub a dry white cotton cloth across the pile ten times with firm pressure. Any visible tint on the cloth is below a 4 and worth a call to the mill.
- Wet a second cloth with room-temperature water, wring it, and press it onto the darkest color for 30 seconds, then rub ten times. A faint tint is a 3; a clear mark is a 2 and the sample should not go to the client.
- For a hand-knotted rug, do the wet test where two strong colors meet, since bleeding shows at the boundary. Note the result on the sample ticket.
What to tell the client and the cleaner
Most crocking complaints are a cleaning problem, not a mill defect. Hot water, high-pH cleaners and over-wetting lift dye that a correct cleaning would not touch. Specify low-moisture or dry-compound cleaning for wool and hand-made rugs, and name a cleaner who works to the WoolSafe or IICRC standard. A new dark rug may tint light socks for a few weeks as loose dye vacuums away; that stops. A rug that keeps marking after three months, or bleeds under a damp cloth, goes back to the mill under warranty, and the sample ticket is the evidence. If a rug gets wet on site, tell the installer to lift it, blot it with white towels and dry it flat with air movement, never heat, and never on a damp slab.
Questions designers ask
What does crocking mean on a carpet spec?
It is the color transfer rating from AATCC 8, the crockmeter test, given as two numbers from 1 to 5 for dry and wet rubbing. A 5 means no color came off on the white test cloth. For residential carpet, 4 dry and 3 wet is the standard, and solution dyed fibers reach 4.5 to 5 on both.
How do you stop a rug from bleeding?
Specify it right rather than fix it later: solution dyed synthetics where it cannot happen, well-washed wool from a mill that publishes colorfastness, and a wet-cloth test on any hand-made rug before it ships. Once installed, keep water and alkaline cleaners off it. A rug that already bleeds can sometimes be stabilized by a specialist cleaner with an acid dye-setting rinse, but that is a repair, not a guarantee.
Which fibers crock the least?
Solution dyed nylon and polypropylene, because the color is part of the fiber. Then properly washed wool. Cotton, jute, viscose and bamboo silk sit at the other end, and deep, saturated colors crock more than pale ones in any fiber.
What are the stages of dyeing, and why do they matter for carpet?
Color can go in at the polymer stage (solution dyed), the fiber or yarn stage (stock or skein dyed), the carpet stage (piece dyed or printed), or in a hand dye house for rugs. The earlier the color goes in, the more it is locked into the fiber and the less there is to crock or bleed. Later stages give the mill more colorways and shorter lead times, which is why most residential wool is yarn dyed and most hand-knotted rugs are skein dyed.
Does lightfastness matter in a bedroom?
Yes, more than people expect, because bedrooms often have the largest windows and the rug sits in the same place for years. Ask for AATCC 16 at 4 or better, rotate the rug twice a year, and avoid viscose and silk on the window side of the room.
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