Reactive Dyeing

TechShop:Reactive Dyeing

This guide is for students who have completed a Health & Safety induction in the Dye labs and have attended a Reactive Dye Workshop.

Reactive Dying with Procion Dyes

To dye cotton, linen, silk and viscose rayon

First: Weigh your dry fabric or yarn then put into warm water to soak.
Soaking for longer periods of time maybe necessary for certain fibres, heavy weight fabrics and hanks. Washing fabric may also help to assist even dyeing.

Do all calculations before beginning to dye.

Using the following calculations work out the amount of ingredients required

  1. Dye; Dry weight of fabric/yarn multiplied by dye percentage divided by 100 = dyestuff required (grams)
    • Please refer to the files in the dye lab for the dye percentage.
  2. Water; 20 multiplied by dry weight of fabric/yarn = water required mls (1 litre = 1000 ml )
  3. Salt and sodium carbonate;

The amount of salt and Sodium depends on the depth of shade and quantity of water.
From the first column select which depth of shade you require, then follow the row across to determine how much salt and sodium you require per litre of water.

Depth of shade Salt Sodium carbonate
Up to 0.5% 30g per litre 3g per litre
0.5% - 2% 40g per litre 4g per litre
2% - 4% 50g per litre 7g per litre
4% - 8% 60g per litre 10g per litre

millilitres of water multiplied by grams of salt divided by 1000 = total grams of salt
millilitres of water multiplied by grams of sodium carbonate divided by 1000 = total grams of sodium carbonate


  1. Fill dye vat with required amount of warm tap water.
  2. Measure out all dyes and chemicals into individual cups or small containers.
  3. Dissolve dye stuff in small amount of hot tap water (ensure it is completely dissolved) and add to dye bath.
  4. Enter wet fabric/yarn and dye for 20 mins, adding salt in 3 portions at 5 minute intervals. When adding anything to dye bath always remove fabric/yarn placing it back in once the chemicals have been dissolved.
  5. Keep fabric/yarn moving in the dye bath whilst dyeing to avoid patchy dyeing.
  6. After the 20 mins, dissolve the sodium carbonate in a small amount of warm water, lift out fabric/yarn and add the sodium carbonate in one portion.||
  7. Continue to dye fabric/yarn for a further 40 minutes. Remember to keep the fabric/yarn moving throughout this period.
  8. Rinse dyed fabric in cold running water until clear, then rinse in hot water using a little detergent, again until clear, then again in cold water.
  9. Use the spin-drier to take off excess moisture and hang on the line to dry.

N.B. Badly dyed fabrics can sometimes be evened out by heating them (if silk) or boiling them briefly (if cotton/linen/viscose) in water with a small amount of detergent.




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