How chlorine destroys colour

Short answer: Chlorine pulls oxygen out of the water and attacks the dye molecules. The bonds break, the colour disappears in patches, and at high concentrations the fibre itself is weakened. That is why chlorine leaves marks that cannot be washed out again.

Chlorine is a strong oxidiser

Chlorine works by breaking down organic molecules, and it does so very effectively. Dye is made of exactly such molecules, so it breaks down quickly on contact. It is the same property that makes chlorine good at disinfecting and harsh on coloured fabric in the wash.

It happens in small amounts too

Chlorine in pool water or in bleach leaves marks on dark colours, even when the amount is small. The effect often appears only once the garment is dry, so it is noticed late. A single splash can be enough to leave a pale spot that survives the next wash.

The fibre is affected as well

Strong chlorine weakens the cellulose and makes the fabric brittle. That is why many garments must not be bleached, and the care label symbol says so. Always follow the label and skip bleach on coloured items. See bamboo hoodie dresses, where care instructions are listed on each garment.

The marks have a typical shape

Chlorine marks often look like pale, irregular areas with a soft edge into the original colour. Sometimes the colour turns yellow or orange instead of disappearing completely. It depends on the dye, so it is hard to predict what a mark will look like beforehand.

Avoiding damage around the house

Cleaning products with chlorine sit in many homes, and a drop from a bottle or cloth can reach clothes. Wear an apron when cleaning and keep the bottle away from the laundry. If something lands on clothes anyway, rinse at once with plenty of cold water. See bamboo clothing for women.

A trip to the pool

Pool water contains chlorine in low doses, but it does its work when swimwear is used again and again. Rinse swimwear in clean water straight away and wash it soon after. Do not leave the wet piece rolled up in a bag, where the chlorine can keep working for hours.

Can a garment be saved

A chlorine mark can rarely be removed, because the colour is broken down and cannot be rebuilt. Sometimes the garment can be dyed again in a darker shade to hide the spot. That works best on plain fabric and needs a garment that tolerates dyeing. See bamboo tops for women in dark shades.

When chlorine belongs

Chlorine has a job in disinfecting and in bleaching white laundry, where there is no colour to lose. That is where it belongs. On coloured clothes there is nothing to gain and a lot to lose, so pick a milder detergent for everyday washing.