Discharging is the process of removing the colour in a garment using bleach. This can create beautiful effects by folding, painting, stenciling or merely throwing the garment in bleach. This page explains the discharging process and the effects of bleach on cotton and wool.
Some Characteristics of Cotton
- Cotton is a cellulosic, natural fibre (Tortora, 1987:62).
- Cotton will not melt, but if ironed under very high temperatures, the fabric can scorch or turn yellow (Tortora, 1987:70).
- Cotton can be washed with natural soaps and synthetic-built detergent,
- Can be dry-cleaned,
- And oxidizing bleach can be used to remove stains,
- But strong chlorine bleach should not be applied directly as it will damage the fibres (Tortora, 1987:72). (Unless the neutralizing process is applied).
Materials to use
- Several water buckets
- Bleach
- Newspapers for the floor
- Paintbrush and other print making patterns, eg. lace
- White blackboard chalk
- Rubber bands
- Gloves
- Black 100% cotton shirt or blouse
Discharge Process
- Tie the shirt in the desired way for a tie-dye effect
- Place the shirt in diluted bleach until the discolouration appears right (check this every 5 minutes) or remove after 1 hour, and
- Rinse and neutralize , or
- Draw the desired pattern with the blackboard chalk
- Separate the layers of the shirt with newspaper so that the bleach does not affect the back of the shirt
- Paint over these lines using a small paintbrush and bleach
- Leave the shirt until the colour appears right, or otherwise after 1 hour, and
- Rinse and neutralize
General pointers to bleaching cotton
- Always read labels for instructions
- If you really want to bleach a garment that says "do not bleach" (eg. to discharge) first test on a sample of the material or hidden part of the garment
- Preferably do not bleach wool, silk, mohair, spandex or fire-resistant fabrics.
- Wear gloves
- Work in a well-ventilated area
- Rinse the garments thoroughly after exposure to bleach
Neutralizing
After bleaching it is important to neutralize the bleaching action, as the bleach will continue to eat (and ultimately damage) the fabric which will leave you with a weak fabric with holes.
I used hydrogen peroxide as this can be obtained at most pharmacies.
This is the neutralizing process I used as found on Up and Dyed
- Prepare 1 - 1,5 gallon (about 6 litres) of warm soap water
- Rinse the discharged garment after bleaching
- Immerse the garment completely in the soap water while swirling it for 30 seconds.
- Add one cup of of hydrogen peroxide while swirling
- Let it lie for 30 minutes stirring every now and again
- Rinse the garment again
- Machine wash and dry
- Bisulfite or metabisulfite
- Thiosulfite
For more info on these products, take a look at Paula Burch's All about Hand Dyeing.
The Acrylic Bow Tie
I wanted to test what bleach would do to this acrylic grey knitted bow tie. I used a little undiluted bleach in a bucket so that patches of the bow tie could soak up the bleach.
- No immediate effect
- After several hours - still no change
- And even after having been rinsed and dried, there was no apparent difference
I also used the above acrylic maroon block of weaving which was too small to make into a bow tie and tested the washing, rinsing and tumble drying effects on the block.
Wash and Tumble-dry results:
- After hand washing and rinsing, the weaving was slightly more fluffed
- After being left in the sun to dry, there was no discolouration or shrinkage
- And after being tumble dried for 15 min there was no change in size
The Merino Bow Tie
Bleaching Results: (Block on right side bleached with undiluted bleach drops poured on parts of the block of knitting.)
- At first there was no change in colour
- And no apparent immediate effect
- After being rinsed with warm water (no neutralizing agent applied), the block was very stretchy (due to the fibres being wet)
- The fibres were also more fuzzy
- And the block seemed weaker
- After having dried, discolouration is evident along with a plastic-like, hard texture, where the wool was exposed to the bleach
Wash and Tumble-dry Results: (Block on left side)- After washing the fibres seemed weaker while still wet,
- And also stretched and fluffed.
- After being tumble dried for 15 min, the fibres are soft and even more fluffed,
- But no shrinkage occurred.
Some Characteristics of Wool
- Wool is a natural protein fibre (Tortora, 1987:102).
- Wool is easily damaged by strong alkali's, thus, mild detergents should preferably be used (Tortora, 1987:113).
- Wool can be washed and dry-cleaned unless indicated otherwise (depending on the finishes applied to the wool).
- Lukewarm water should be used for washing.
- Handling wool too much as in hand washing, may damage the fibres.
- Friction causes felting and shrinkage, thus wool should not be tumble-dried.
- Chlorine bleach will damage the fibres, but hydrogen peroxide can be used to bleach.
- Iron temperatures should not go above 93 degrees Celsius as heat may damage wool (Tortora, 1987:114).
Reference List
Burch, P.E. 2014. How can I neutralize the damaging effects of chlorine bleach? Paula Burch's All About Hand Dyeing. [Online] Available: www.pburch.net/dyeing/FAQ/neutralizingdischarge.shtml
Buzzle.com. 2014. Is Bleaching Clothes Safe? Buzzle.com. [Online] Available: www.buzzle.com/articles/is-bleaching-clothes-safe.html
Ericson, L. (ed.) 2008. Dyeing with Bleach. Threads. [Online] Available: www.threadsmagazine.com/item/3720/dyeing-with-bleach/page/all
Tortora, P.G. 1987. Understanding Textiles (3rd ed.) New York: Macmillan Publishing Company
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