Sodium thiosulphate is is used for loads of everyday things, however to reduce confusion I’m going to just straight to what I use it for within dyeing.
When reverse dyeing I use household bleach to remove the colour from fabrics, however bleach will continue to break down fibres even after it’s washed out. This causes fabrics to disintegrate. That’s where sodium thiosulphate flexes it’s muscles. A solution of sodium thiosulphate and water will de-chlorinate the bleach and stop the chemical reaction – protecting the fibres. Once the bleach has been rinsed from the garment soak in the solution for half an hour before washing as normal, and then you are good to go!
Use 1 tablespoon of sodium thiosulphate per 10 litres of water.