2.3 Experimenting with fabric dyeing
➤ Material Science
This workshop aims to create an understanding of natural dyeing techniques. You will also learn what chemistry reactions take place when you dye clothes.
A lot of things! Check below.
Textile knowledge, understanding natural chemical reactions
For this activity you will need a lot of things. Check the list below.
Different sizes of beakers - mostly big ones
Fabric swatches – cotton, silk or other natural fibres (natural dye doesn’t colour synthetic fibres easily)
Natural products: turmeric (dried or fresh), red cabbage
Base: baking powder
PH neutral soap
Paper, clamps, string
Document your experiment with photos videos, drawings and notes. This might become handy later on. For every dye swatch you make, attach it to a piece of paper and write a short version on the process. I.e. Turmeric, 20 min. dye bath, no mordant
For as long as people have been able to spin and weave, we have been able to dye fabric. In the past we only used natural dyes from plant and insects, using techniques such as Indigo (colouring obtained from a plant), Cochenille (colouring obtained from an insect living on cacti) and Purpur (colouring extracted from a snail).
Today almost all textiles are coloured with synthetic colouring, most of which is produced through the use of oil. Natural dyes are not typically used in the industry because of their lack of colour fastness. Synthetic colouring has the power to obtain long-lasting colours that don’t fade. Most colouring processes require after-treatment, which is often bad for the environment. This treatment usually involves a lot of chemicals, including formaldehyde CH2O, a toxic gas with negative effects on people and the environment.
Shockingly large amounts of chemical waste ends up in water supplies. In China, where most textiles are made, the drinking water is so polluted that an estimated 320 million Chinese people have no access to clean drinking water. 72 toxic chemicals are found in the drinking water as a direct result of the textile industry. An estimated 90% of the groundwater and 70% of all China’s rivers and lakes are polluted.
Experimenting with fabric dyeing
Gather your fabric swatches. Make sure they are all clean and soaked evenly in water. Otherwise your colours will not dye evenly.
Fill a beaker of water with 8 parts of water and 2 parts vinegar and heat until boiling. Add your textile and let it simmer until your dye baths are ready. The vinegar only works as a mordant in some natural dyes.
Most common mordants used in in natural dye are metal salt solutions:
Al, CR, Cu, Fe, Sn
But we will use vinegar, since disposal of many metal salt solutions can be a problem.
When dying with substantive dye the mordanting process is not necessary. But the swatches still need to be soaked previously.
Step three depends on which dye you are going to use: red cabbage or turmeric.
Fill another beaker with about ½ liter of water, to make a dye bath.
Red cabbage is a substantive dye and has anthocyanin pigment, which means that it’s water-soluble. Therefore you don’t need a mordant for this type of dye. The pigment is, however, directly affected by the PH value. The PH value changes, when acid or base is added.
As the water in the dyeing bath reaches a high temperature, add the cabbage, as you feel suitable. The more you add the more it colours. One-quarter cabbage head to one l water is suggested. Let it boil until the water catches the colour density you want.
Pure some strained cabbage water in two bowls. Add acid to one of them.
Dip a swatch in each of the dyeing baths. And let it sit for at least 15 minutes. The longer it stays, the more colour it obtains. If you have several different pieces of textile material try to see how the colours vary from textile to textile.
Turmeric is a fugitive dye, meaning the colour will fade when exposed to sunlight and when washed. Using fresh turmeric will give a stronger colour, but dried works as well. You do not need to use a mordant, but using metal mordant will create a darker colour, where no mordant creates a brighter colour – depending on the type of mordant.
10 grams of turmeric
0,5 L of water
Create smaller or larger dye baths, depending on how much fabric you want to dye. The fabric needs to be completely covered.
When boiling, let it simmer for about 15 minutes. Add three mordanted fabric swatches.
Occasionally stir the mixture.
Shades of yellow:
For every 5 minutes take out a swatch
How does the length of colouring process affect the colour density?
When you have finished dyeing your fabric, wash it.
Wash the fabric in cold water, with PH neutral soap. PH-neutral soap washes out excess colour without interfering with the dyeing process.
Happy with your colour?
Otherwise you can always go back and to the dyeing bath and colour the textile again!
Now you've learned about Natural Fibres and Man-made Fibres!
Introduction to textiles
Natural and Man-made fibres