How to Dye Purple and Mauve with Madder (Iron Mordant Recipe)

Madder is famous for reds, but with an iron mordant it gives beautiful mauves and purples. This recipe by natural dyer Charlotte Treglown dyes 100 g of cotton fabric. For the classic red version, see our madder dye kit for red shades.

Ingredients (for 100 g of fabric)

• 100 g undyed cotton fabric, such as our undyed fabric by the meter
• 20 g soda ash (sodium carbonate)
• 100 g madder root powder
• 2 g iron (ferrous sulfate)

Equipment you will need

• A well-ventilated space and a heat source you can control
• A thermometer that reads up to 100 °C (212 °F)
• A large stainless steel or enamel pot with a lid, used only for dyeing (never for food again)
• A plastic bucket
• Tongs or a wooden spoon
• Protective gloves, and a dust mask (optional) when handling powders

Before you start

First you scour the fabric, then you prepare a madder dye bath, mordant the fabric with iron and dye it. The iron mordant is what turns madder's usual red, orange and pink toward mauve.

• Keep iron equipment separate. Tiny traces of iron left on a pot or spoon will darken future dye baths.
• Protect surfaces and hands. Iron sulfate stains wood and skin black, so cover your work surface and wear gloves.
• Natural does not mean harmless. Follow the safety notes, and wash all equipment between stages.

Step-by-step instructions

Step 1: Scour the fabric

Scouring removes oils, starch and other residues from manufacturing, so the dye takes evenly. Simmer the fabric for 90 minutes in the dye pot with 20 g of soda ash (sodium carbonate), then rinse well. Or wash it on the hottest washing machine cycle (at least 90 °C / 190 °F) with the soda ash in the drum. You can dry the fabric and label it "scoured" for later, or continue straight away.

Step 2: Make the dye bath

Put the madder powder in the pot and cover it with plenty of hot tap water. Heat the bath to 60–70 °C (140–160 °F) and hold it there for one hour. Do not let it get hotter, or the colors will turn brown and dull.

Step 3: Mordant with iron

Thirty minutes into the dye bath's heating time, put the fabric in a bucket of cold water to wet it thoroughly. Ten minutes before the dye bath is ready, take the fabric out, put on gloves and dissolve the iron sulfate in the bucket water. Return the fabric and stir so it soaks evenly. The water may turn a pale rusty color; that is fine. Leave it for about 10 minutes, then wring it out lightly.

Step 4: Dye the fabric

Add the fabric to the dye bath and keep it at 60–70 °C (140–160 °F) for another hour. Then turn off the heat and let the fabric cool in the bath for several hours or overnight, stirring now and then.

Wring the fabric out well and hang it to dry out of direct sunlight. Once dry, brush or rub it gently to remove any loose madder powder. Wait two to three days before washing.

Washing

Hand wash the dyed fabric with a pH-neutral detergent and rinse well. Some color will come out in the first wash; this is normal. Press with a hot iron.

Tips for purples and mauves

• If you want reds and purples from the same madder, take out part of the dye bath and dye the iron-mordanted fabric in it separately.
• For darker plum tones, use a little more madder or give the fabric a second dye bath.
• Learn more about iron in our guide to mordants for natural dyeing.

Related: Everything to know about madder · How to dye with madder root powder · Shop natural red dyes