What Is Bleach Wash?

How is bleach wash made?

Bleach wash is made by immersing finished garments or fabric in a bleach bath that strips part of the dye, then removing the leftover chlorine with a neutralising rinse. Patents on finishing denim describe dip bleaching with sodium hypochlorite as the route to relatively uniform bleaching, followed by a step that removes the chlorine with a reducing agent such as sodium thiosulfate.

A 2011 study from the University of Rajshahi shows typical conditions. The researchers desized denim trousers, then bleached them in a hypochlorite bath with soda ash at pH 10.5, testing temperatures of 40–60°C and times of 20–40 minutes. A five-minute neutral wash in “hypo” (2 g/l at 40°C) followed.

Where does bleach wash come from?

No inventor or first date is documented for bleach wash. The National Library of Scotland notes that surfers in the 1960s, wanting soft, faded jeans, bleached their denim with chlorine or sunlight, and that in the early 1980s punks splattered their jeans with bleach for a home-made marbled effect, a look tied to punk fashion.

Industrial fading appears in US patents by 1978. A US patent assigned to BASF Wyandotte and filed in December 1978 aimed to fade blue jeans evenly, “without streaking”, and named liquid sodium hypochlorite as one bleach that could be used. Its background says suitably faded jeans had until then been obtained by repeated washings.

What does bleach wash do to denim?

Bleach wash makes denim paler, less stiff and more absorbent, but also weaker and slightly lighter in weight. The Rajshahi study measured these changes on bleached denim, a twill woven from cotton:

• Colour: the shade dropped significantly after hypochlorite treatment.
• Hand: unwashed samples were stiffer, harder and less absorbent than bleached ones, though the bleached surface was rougher.
• Strength: at a 10 g/l dose, warp tensile strength fell from 246 kgf to 219 kgf (11%) at 40°C, and to 162 kgf (34%) at 60°C. Weft strength fell by 6% and 16% respectively.
• Weight: the 381 gsm test fabric lost about 1–6% of its weight, depending on conditions.
• Surface: microscope images showed cracks and loosened fibres on the bleached cloth.

An earlier patent puts it more bluntly: chlorine bleaching agents “are known to be very destructive to cotton”.

How is bleach wash different from acid wash and stone wash?

Bleach wash removes colour chemically in a liquid bath, stone wash removes it by abrasion with pumice, and acid wash combines the two by tumbling garments with stones soaked in an oxidiser.

The two names are easy to mix up because acid wash also relies on an oxidiser, such as chlorine bleach, rather than acid. A 1994 patent draws the line: dipping in sodium hypochlorite gives relatively uniform bleaching, while pumice impregnated with it gives non-uniform bleaching. Both are routes to distressed denim, alongside localised effects such as whiskering.

How does bleach wash appear on a clothing label?

Bleach wash does not appear on the fibre-content label, because it is a finish, not a fibre: a bleach-washed cotton garment is still labelled by its fibres. Where the label matters is bleach care. Under the US Federal Trade Commission’s Care Labeling Rule:

• If chlorine bleach would harm the item but non-chlorine bleach would not, the label must say “Only non-chlorine bleach, when needed”.
• If all commercially available bleaches would harm it, the label must say “No bleach” or “Do not bleach”.
• A label need not mention bleach only when all commercially available bleaches can be used regularly without harming the item.

How do you tell good bleach wash from poor bleach wash?

A well-done bleach wash is even, free of a yellow cast in the pale areas, and leaves cloth that still feels sound at the stress points. Check a pair of jeans or a denim jacket in daylight:

1. Look for streaks. Lay the garment flat and scan for stripes or blotches where an even fade was intended. A 1994 patent notes that sodium hypochlorite is so strong that the degree of bleaching is not easy to control, and the 1978 patent set “without streaking” as its goal.
2. Check the palest areas for yellow. The same 1994 patent lists yellowing of blue denim among the problems seen in bleached denim.
3. Pinch and pull at the stress points. Tug gently at the knees, seat and pocket corners. In the Rajshahi study, higher bleach doses and hotter baths each cut tensile strength further, so very pale bleached denim deserves the closest check.
4. Read the care label. Note what it says about bleach before you wash it (see the rules above).

How do you care for bleach-washed clothes?

No care standard specific to bleach-washed clothes was found, so follow the garment’s own care label. In the US, that label must tell you if chlorine bleach, or any bleach, would harm the item. Because the finish has already weakened the cotton, adding more chlorine bleach at home is best avoided unless the label allows it.

Is bleach wash sustainable?

No source found measures the overall footprint of bleach wash, but the evidence available points to costs. A 1994 patent warns that chlorine gas is given off if the hypochlorite solution is heated. A 1992 patent lists chlorine bleaching among the fading methods that damage fabric and affect its wear life, and proposes ozone instead; its inventors reported that ozone-treated fabrics lost less warp strength than chlorine-bleached garments, though that is the patent holders’ own comparison, not an independent test.