Chrome (Potassium Dichromate) Mordant - 250g


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    Chrome mordant for use to colour protein fibres (wool, hair and silks) with natural dyes.


    Due to requirements set out by REACH Regulation (Regulation (EC) No 1907/2006), Potassium Dichromate can only be purchased by educational establishments. To confirm that your order is for an approved buyer please phone 01483 565800 or email your details to us at

    Chrome mordant links chemically with the fibre and creates attachment points which bond with the colourant from natural dyes creating light and wash fast colours. It alters the colour obtained from dye plants (depending on the plant used) adding shades of orange through to magenta, browns and purples. We encourage experimentation and recommend careful record keeping to help reproduce colours in future dye sessions.

    It helps to soak the wool in warm water and squeeze out excess before adding to the mordant bath. For every 250g of the dry wool or silk, use 5g of chrome mordant in 5 litres of water. Add 10g of Cream of Tartar to help soften the fibre and brighten the colours. Gradually heat the mordant bath to around 80°C for 30 minutes and allow to cool slowly. Remove the wool and squeeze to remove excess liquor.

    After mordanting, the wool can be simmered with any of the natural dyes. It may help to place the dyestuff in a mesh bag before adding to the dyebath. Simmer for approximately 30 minutes and turn off the heat. Allow the wool to cool slowly in the dyebath before removing it. Gently rinse out excess dye in clean water.

    Please note the following Health & Safety guidance:

    Danger: May intensify fire; oxidiser. Toxic if swallowed. Harmful in contact with skin. Causes severe skin burns and eye damage. May cause an allergic skin reaction. Fatal if inhaled. May cause allergy or asthma symptoms or breathing difficulties if inhaled. May cause respiratory irritation. May cause genetic defects. May cause cancer. May damage fertility or the unborn child. Causes damage to organs through prolonged or repeated exposure. Very toxic to aquatic life with long last effects.

    Do not handle until all safety precautions have been read and understood. Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking. Keep away from clothing and other combustible materials. Wear protective gloves/protective clothing/eye protection/face protection. If exposed or concerned: Get medical advice/attention. IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower. IF SWALLOWED: Rinse mouth. Do NOT induce vomiting. Do not breathe dust. IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Avoid release to the environment. Collect spillage.

    CAS No. 7778-50-9 EC / List No. 231-906-6

    Download the Material Safety Data Sheet (SDS) for further information