It’s not easy to dye cotton fabric a washfast and lightfast blue with natural dyes (except with indigo and woad). After some experiments with natural blue dye materials, and different mordants and modifiers, I finally found out that red cabbage dye + iron mordant produce a beautiful washfast and lightfast blue – I’ve read that iron in the soil will make hydrangea flowers more blue so I thought that iron might probably help to fix the blue color to the fabric. So in this tutorial I’ll show how to dye cotton and viscose rayon fabric blue with red cabbage.
- red cabbage
- prewashed fabric or yarn *
- pot and bucket
- rubber gloves
- DIY iron liquor
* I used unbleached and white cotton fabric, rayon chiffon and white cotton yarn.
Wear rubber gloves and old clothes to protect your skin and clothes.
Mordant Fabric With DIY Iron Liquor
Pour DIY iron liquor into a bucket. Dilute iron liquor with enough water so that you can submerge the fabric. Wet the fabric/ yarn with water, then submerge it in the iron liquor solution. Let it soak for some seconds in the iron mordant, squeeze out excess mordant. Let the mordanted fabric dry or use it right away.
Chop the red cabbage and put it in cold water because natural blue colors – anthocyanins – are heat-sensitive.
I used just the limp outer cabbage leaves – the rest we used for eating.
Let the red cabbage soak till the water turns dark blue like ink. Mine took about one day.
Put the fabric or yarn into the dye solution. Add water if necessary (more water won’t weaken the dye solution, but the fabric will dye more evenly). Stir the fabric occasionally. Let the fabric soak so long till you like the color – bear in mind that wet fabric is darker than dry fabric; also the color will bleed during the first wash.
I let the fabric and yarn soak about 12 hours.
The fabrics and yarn on the left are already rinsed in water. The cotton fabric and yarn took the color better than the viscose rayon which only became pale blue.
Here’s how the fabric and yarn looked after the washing machine.