Why a New Black Hoodie Rubs Off on Everything

A new black hoodie goes on over a white tee at seven in the morning, the day turns humid, the hoodie stays on because the office is cold, and by evening the tee collar has gone grey and a pale bag strap has a smudge on it. The hoodie looks perfect. Everything it touched does not.

That is crocking. Colour rubbing off a dyed fabric onto another surface. It is not fading, it has its own test methods, and on a well finished cloth it settles after the first few washes. On a badly washed-off one it can go on for months.

Crocking is a measured property

The American Association of Textile Chemists and Colorists publishes a method for this. AATCC TM8, Test Method for Colorfastness to Crocking: Crockmeter, in the TM8-2016e(2022)e edition, covers textiles made from all fibres in the form of yarn or fabric, whether dyed, printed or otherwise coloured. A piece of the coloured fabric is rubbed with a square of white test cloth under controlled pressure and stroke, and the white cloth is then graded for how much colour came across, against the Gray Scale for Staining or the Chromatic Transference Scale. Top grade means the square came away clean.

Two runs are made. One with the white cloth dry, one with it wet with water. The second is the one worth knowing about.

The international equivalent is ISO 105-X12, colour fastness to rubbing. In a 2023 study in Heliyon on cotton knit, Ghosh and Rupanty graded rubbing fastness by ISO 105-X12 and reported, for the black shade dyed the conventional way, grade 4 dry and grade 2 to 3 wet. Roughly two grades worse once water is involved. One study on one set of fabrics, so take it as an illustration rather than a rule. It does explain why the trouble shows up on a sweaty day and not a dry one.

Sweat is its own test

There is a separate method for that too. AATCC TM15, Test Method for Colorfastness to Perspiration, current edition TM15-2021e, wets a coloured specimen in a simulated acid perspiration solution, presses it against undyed fibres under a fixed load and holds it near body temperature for hours. The specimen is then graded for colour change and the undyed fibres for colour transfer.

Nothing in a laboratory is a Tuesday commute, but the setup is a fair sketch of one. Damp cloth, body heat, steady pressure at the collar and shoulder. Those are the places a pale layer underneath goes grey first.

Why the colour is loose in the first place

Most heavy cotton in black or a deep colour is dyed with reactive dyes, which form a covalent bond with the cotton. Cotton Incorporated's technical bulletin Producing Colorfast Cotton Knits puts dye selection first among the things that decide whether colour stays put, and reports that reactive dyes hold up better than vat, direct and sulphur dyes through repeated home laundering.

The catch is that not all of the dye bonds. A share of it hydrolyses and sits in and on the fibre attached to nothing. The Heliyon paper puts the figure for conventional reactive dyeing at 30 to 50 per cent of the applied dye not covalently linked to the fibre. That loose fraction has to come out at the mill by washing off, a run of rinses and hot soaping steps, sometimes followed by a cationic fixing agent. Cut the wash-off short to save water, time and heat, and the dye that should have gone down the drain leaves with the garment instead. It comes off later, on a tee shirt or a car seat.

Two things stack on top of this:

Depth of shade. A deep black carries far more dye than a heather grey, so the unfixed fraction is bigger in absolute terms even when the dyeing was done properly.
Surface fibres. Heavy loopback and fleece have plenty of fibre ends standing off the surface, and those ends carry colour and rub easily. The bulletin describes the mill-side answers, cellulase enzyme treatment and singeing, both of which take the protruding fibres off before the garment reaches anybody.

Fading and crocking are different complaints

They get treated as one, and they are not. The same bulletin describes what it calls phantom colour loss. Black cotton interlock laundered twenty times measured an average of 8.7 per cent down on colour strength. After a cellulase enzyme treatment took the surface fuzz off, it regained close to all of that. The colour had not gone anywhere. Raised fibres were scattering light and the eye read it as faded. So a hoodie that looks chalky after a summer of wear may not have lost dye at all, while a hoodie leaving grey on a white tee definitely has loose dye at the surface.

What actually helps

The aim for the first month is to get the loose fraction out in the machine rather than on your clothes.

Wash it before the first wear. Cold, alone or with the same colour. Expect tinted water. That is the point.
Turn it inside out. The face takes less abrasion against the drum and the rest of the load.
Do not pack the drum. Cotton Incorporated ran the same four-pound load in 14 gallons of water and in 18 gallons in a top loader. After twenty wash and tumble-dry cycles the low-water condition measured seven to nine per cent lower in colour strength across every finish tested. More water, less fabric grinding on fabric.
Leave the softener out. The bulletin flags silicone softeners as suspected of aggravating fuzzing on cotton knits, with poorer colour retention alongside it. More on what softener does to heavy fleece.
Give it two or three washes before it meets anything pale. A cream jacket, a light car interior, a canvas bag. Just at the start, not forever.
Do not wear it damp against something you care about. The wet grade is the low one. A hoodie worn over a sweaty tee all shift is the hardest version of the test.

Our own washing notes are on the care page, and they are short on purpose.

What does not have evidence behind it

Vinegar or salt in the wash to set the dye. It is the most repeated laundry advice going and we could not find a test method or a mill process that backs it for reactive-dyed cotton. Fixing agents in a dyehouse are cationic products applied under controlled temperature and pH after dyeing, which is not what a cup of vinegar in a rinse cycle does. It costs nothing, so nobody needs to fight about it, but it is folklore rather than a tested step, and a poor reason to put a new black garment in with pale laundry.

When it is a fault

Some dry rub-off from a deep black in the first week or two is common. Colour still transferring to a white tee after four or five washes is not. At that point the wash-off was inadequate, which is a manufacturing problem rather than a care problem. That is a return, and worth saying plainly to whoever sold it.

The label will not settle the question. In Canada the Competition Bureau's textile labelling requirements oblige a consumer textile article to carry fibre content by generic name and percentage for every fibre at 5 per cent or more, plus the dealer's name and place of business or a CA identification number. Care instructions are not on that list. As the Bureau puts it, care labelling, in words or symbols, is a voluntary program in Canada, and where given it must not be false or misleading. Dye class and crock grade are not there either. More on that in what a hoodie label has to tell you.

Where symbols are given, the dots are temperatures. The Office of Consumer Affairs guide reads one dot as 30 degrees, two as 40, three as 50. The standard behind those symbols, CAN/CGSB-86.1, was withdrawn by the Canadian General Standards Board in October 2017. The symbols are still in wide use, which is worth knowing before treating a wash symbol as a legal instruction.

Cold water, a full drum, no softener, two or three washes before the hoodie meets anything cream. That covers most of it.

Sources

American Association of Textile Chemists and Colorists. AATCC TM8-2016e(2022)e, Test Method for Colorfastness to Crocking: Crockmeter. members.aatcc.org/store/tm8/481
American Association of Textile Chemists and Colorists. AATCC TM15-2021e, Test Method for Colorfastness to Perspiration. members.aatcc.org/store/tm15/482
Cotton Incorporated. Technical Bulletin TRI 3017, Producing Colorfast Cotton Knits, 2004. cottoninc.com
Ghosh J, Rupanty NS. Study on a cationic agent-based salt-free reactive dyeing process for cotton knit fabric and comparison with a traditional dyeing process. Heliyon, 2023, volume 9, issue 9, e19457. pmc.ncbi.nlm.nih.gov/articles/PMC10558619
Competition Bureau Canada. Textile labelling requirements. competition-bureau.canada.ca
Innovation, Science and Economic Development Canada, Office of Consumer Affairs. Guide to Apparel and Textile Care Symbols. ised-isde.canada.ca