How to dye silk with Procion MX Dyes - Traditional Method


Most Important

Please note that FastColours do not give any guarantee on the quality and performance of the dyeing achieved as the process is outside the control of the company. It is the responsibility of the purchaser to ensure that they understand the risks involved in carrying out this process and that FastColours LLP do not have any subsequent liability. Please contact the company if in doubt.

Dyeing is reasonably straight forward. The following is a general guideline of how to dye these fibres. Recommended Safety Precautions Safety spectacles, gloves, dust mask, lab coat/apron must be worn when handling dyes and chemicals.

This information sheet covers the traditional method of dyeing silk with PROCION MX dyes from a dyebath containing common salt and soda ash.

When dyed with PROCION MX dyes, silk retains all its unique properties of lustre, softness, and handling.

A very wide range of colours can be achieved when dyeing with PROCION MX dyes – from subtle pastel colours, through to very bright vibrant colours, as well as dark, subdued shades.

The colour fastness achieved when using PROCION MX dyes is excellent, and when dyeing very deep shades, FIXITOL P Liquid can be used as an after treatment to further improve fastness to washing of the dyed silk.

Before commencing with the dyeing operation on silk, it is important to ensure that the silk has been efficiently de-gummed in order to allow the fibre to easily accept the dye PREPARING FABRICS FOR DYEING AND PRINTING

In ‘hard water’ areas, it is important to use CALGON PT in the dyebath to eliminate the effects of calcium and magnesium salts in the water. If CALGON PT is not used when dyeing in hard water, then the resultant dyeing will be weaker and duller.

When dyeing silk from a dyebath, the temperature can be around 20oc, but it is better to use tepid water at 40oc, as this speeds up the reaction of the dye with the silk.

There are two additions that need to be made to the dyebath to assist the dyeing:

COMMON SALT - This needs to be added as it salts the dye onto the fabric. Without salt, the majority of the dye would remain in the dyebath.

SODA ASH - Once the salt has salted the dye onto the fabric, the purpose of the Soda Ash is the ‘fix’ the PROCION MX dyes onto the fabric.


To calculate the amount of dye, common salt and soda ash needed in the dyeing, it is important to weigh the fabric whilst it’s dry and determine the amount of water needed in the dyebath. As a guide, 100g of lightweight silks such as Habotai, Georgette or Crepe de Chine will need to be dyed in approx. 3 litres of water to be able to move the fabric around and achieve an even or level dyeing.

If we assume, we are dyeing 100g of silk in 3 litres of water, then the amounts of chemicals are as follows:

Shades Procion MX (g) Common Salt (g) Soda Ash (g)
Pale 0.1 to 0.5 60 3
Medium 1.0 to 1.5 80 6
Heavy 2.0 to 4.0 100 10

Method using Washing Soda + Soda Ash, Soda Ash + Sodium Bicarbonate and Washing Soda + Sodium Bicarbonate have all been recommended in various publications, but the original technique using Soda Ash as recommended above is still the most reliable method.


Measure 3 litres of water at 40oc into a suitable container for dyeing (a plastic bowl or bucket is ideal). In hard water areas, add 2g CALGON PT to the water and stir to dissolve.

Weigh out the common salt, add it to the bucket/bowl and stir until dissolved.

Weigh out the PROCION MX dyes and dissolve in a little tepid water. When fully dissolved, add to the bowl/bucket and stir well.

Add the silk to be dyed to the dyebath and stir gently with a wooden or plastic spoon/stick. Leave, with occasional stirring, for 30-45 minutes, by which time the majority of the dye will have been salted onto the fibre.

Weigh out the Soda Ash and dissolve in a cup full of hot water. Add the Soda Ash solution to the dyebath, making sure that the concentrated solution of Soda Ash does not come into direct contact with the fabric (If possible, lift out the fabric with the stirring stick whilst adding the Soda Ash solution).

Continue dyeing for 30-45 minutes with occasional stirring, after which time, the Soda Ash will have fixed the PROCION MX dye onto the fabric.

Pour the contents of the bowl/bucket into a sink and rinse the silk thoroughly in cold, or preferably, tepid water until the water runs clear.

Fill the bowl/bucket with hot water 60oc, add 5ml METAPEX 38 Liq (soaping agent), add the dyed fabric, stir well and leave for 10 minutes.

After hot soaping or machine washing very heavy shades, there may still be some unfixed dye giving a stain in the water. In this instance, fill a bowl with tepid water 40oc and add 5mls of FIXITOL P liquid stir and leave for 5 minutes. Then put fabric directly into spin dryer followed by iron drying.