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.

Itofix FC Reactive Dyes will successfully dye cotton and other cellulosic fibres

Dye Preparation

Before commencing with the dyeing, it is important to check that the fabric is reasonably clean and free of sizes, starches or oils. If in doubt, give the fabric a hot machine wash at 60oc with washing powder before commencing dyeing.

Using soft water is better than using hard water. 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.

Weigh the dry fabric to be dyed.

The amount dye needed is a percentage of the weight of fabric/article. For light shades you would need about 0.5%, medium shades 1% to 2% and for darker shades 3% or more.

Weigh the dye & make a paste using cold water.

Add hot water to this paste whilst stirring continuing to stir until all the dye is dissolved.

Allow cooling, the dye is now ready to use.

The amount of Glauber’s salt (Sodium Sulphate) and Soda Ash (Sodium Carbonate) is dependent on the depth of shade. The lighter the colour, the less chemicals are needed. Please refer to the Salt & Alkali table in this note.


Heat water to 40°C.

Add Water Softener (if required) and Glauber's Salt - see table for amount, run for 10 minutes.

Heat to 50°C (Lower temperatures will give a lower yield).

Add dyes, run 30 minutes.

Add Soda Ash (Sodium Carbonate) over 30 minutes - see table for amount, run for 10 minutes (by portions or progressive dosing).

Run for 40 to 60 minutes at 50°C (Lower temperatures will give a lower yield).

Drain and do a cold-water acid rinse with white Vinegar 10-15ml/l or 1ml/l with 80% Acetic Acid.

To achieve the best colour fastness, it is essential to do the cold rinse and acidification before doing the hot wash stage.

Soap off using Itoscour LJ350 at 100°C (or highest temperature possible). Click on the link to see how to use it.

Improve the wash fastness by using Itofix EZF as a fixing agent

Salt & Alkali Table

Dye Strength % Fibre weight Glauber’s Salt Soda Ash
Pale 0.3%-0.6% 20g/l 15g/l
Medium 1.0%-1.5% 40g/l 20g/l
Heavy 3.0%-5.0% 80g/l 20g/l

Sodium Carbonate (Soda Ash) - prices and information: Sodium Carbonate

Sodium Sulphate (Glauber's Salt) - prices and information: Sodium Sulphate