Fibre Reactive Dyeing

Fibre reactive dyeing using Procion MX type dyes Procion MX type dyes are most suitable for cellulose fibres from plants – cotton, linen, hemp, ramie, bamboo etc. and also synthetic fibres made from cellulose – viscose, rayon and tencel (lyocell). Procion MX type dyes are “cold water” fibre reactive dyes resulting in permanent colour that is very wash-safe. The optimum temperature range for a Procion MX type dye bath is 24° to 35°C (it seems the “cold” is relative). They are considered non-toxic when used correctly. The patent on “Procion MX” has expired, so each supplier now has its own generic version (hence “Procion MX type” dye). Colour ranges seem to vary greatly depending on the supplier. These dyes require the addition of two chemicals; a salt (usually common salt, sodium chloride, or urea is used) to control dye solubility, and a dye activator (normally soda ash, sodium carbonate) to increase the pH (basic/alkaline) of the dye bath so that the dye will react with the fibres.

Silk can be dyed with Procion MX type dyes using the same method as for cellulose fibres. However, unless exposure to soda ash is limited, it will take away some of the sheen of the silk and can give it more of a stonewashed appearance. And the colours on silk are not as predictable nor the same as on cotton. In particular, mixed colours tend to shift one way or another. Black is particularly not recommended for silk dyeing.

Protein fibres such as wool and silk can also be dyed using Procion MX type dyes under hot, acidic conditions, but is not highly recommended as many of the colours break down under the high heat that wool needs in order to dye properly. The method involved is also more complex than for dyes like Landscapes and Gaywool.

Safety and Equipment

Procion MX type dyes are considered non-toxic if used correctly, however it is possible to become sensitised to the dyes, and they are particularly hazardous when in powdered form.

  • Store dyes and associated chemicals in closed containers in a cool, dry place out of reach of children. Clearly label all solutions and containers.
  • Avoid contact with dyes – wear a dust mask when measuring dye powder and gloves when handling dye in any form. Wear an apron or old clothes.
  • Work in a well ventilated area. Do not eat or drink in areas where dyes and chemicals are used. If at all possible, do not use the kitchen (if you must, then make dye solutions from the powders somewhere else – eg. the laundry or outside)
  • Cover work surfaces with plastic or damp newspaper to protect them. Clean any spills up quickly.
  • All equipment used for fibre dyeing and associated chemicals should never be used subsequently for food preparation. Label equipment so it cannot be mistaken for general kitchen equipment.
  • Keep dye baths, especially hot liquids, out of reach of children.

Keeping Records

It is a good practice to keep records of the dyeing you do. Dyeing is something of an unpredictable art – different fibres will react differently with dyes depending on the circumstances (colour of the starting fibre, soaking/cooking/curing time etc.). Keeping records is especially important if you are mixing colours and wish to be able to repeat the colour again at a later date. And if you record that the dye bath does not exhaust (usually due to too much dye), then you can reduce dye wastage by using less in subsequent dyeing. And if something unexpected happens – record it – it might be useful to know for subsequent dye jobs.

Fibre preparation

To know how much dye to use we need to know how much fibre we are dyeing.

  • Weigh the fibre to be dyed while it is dry. Record the dry weight of the fibre on the appropriate record sheet.

If you are dyeing yarn, wind it into a skein. Make sure the ties on your skein are reasonably loose. If they are too tight then dye circulation will be poor and the colour will be patchy and light around them.

Before the yarn/fibre is placed into a dye bath, it must be thoroughly wetted-out. Wetting-out saturates the fibre with water. The addition of detergent helps to remove air trapped in the fibres by reducing surface tension. The fibre must be saturated before dyeing so that the dye can penetrate the fibre, resulting in even colour.

Synthrapol is an industrial strength surfactant developed for textile industry for removal of excess dye from fabric. Dilute ½ tsp of Synthrapol per litre of water to make a wetting out solution for your fibre. How long you should leave the fibre wetting out will vary between fibre types. Overnight soaking is preferred.

A detergent + water solution is a suitable substitute for Synthrapol: use ordinary liquid dishwashing detergent eg. Morning Fresh, Trix etc. DO NOT use Wool Wash or similar products – they contain oils and softeners that will interfere with the dyeing process. Add a squirt of detergent to the water and stir until mixed before adding the yarn/fibre to be wetted-out.

When dye painting warps or skeins, the wetting out has the additional purpose of holding the necessary dye auxiliary chemicals in the yarn. Follow the directions given in the relevant method.


All measurements given in these instructions use Australian standard measures.
1 teaspoon (tsp) = 5 mL
1 tablespoon (tbsp) = 20 mL
1 cup = 250 mL

Sourcing Chemicals

Soda ash (sodium carbonate), sometimes labelled “pH increaser”, often found as a pool chemical (note: this is not the same as bicarb. soda, sodium bicarbonate). Obtain from pool chemical suppliers or cleaning agent suppliers.
Urea: Usually used as a fertiliser and can be purchased in 20 kg bags from agricultural suppliers (cheaper per kg).
Smaller quantities: eg. Mitre 10: 2.5 kg $7.50
Foam brushes: a large packet of various sizes $2 can be found in places like “Crazy Clarks”, “The Warehouse” or “Reject Shop”.
Salt, detergent, paddle pop sticks: supermarket

Immersion dyeingWarp or skein painting