3. Dyeing with direct dyes

General information on the dyeing process

The material to be dyed is always weighed dry before writing the recipe. Thereafter, the fabric is washed or rinsed in order to get even results. Do not use fabric softener in the pre-wash. Many fabrics contain finishing chemicals, which may affect the results. When dyeing old clothes, it is worth noting that dye does not usually adhere to stitching, sweat marks may be more visible, and it may be difficult to cover stains.

The original colour of the material affects the results and the choice of shades in accordance with colour theory. When blue fabric is dyed with red dye, the result will be purple in tone. It is not possible to achieve a lighter shade by dyeing. However, the fabric’s darkness can be utilised when hoping to achieve a darker shade.

The amount of dye and auxiliary chemicals required depends on the dry weight of the material and the desired colour. When dyeing with Dylon, the maximum amount of dye, or so-called full shade, is 2–3% of the material’s dry weight. With black or dark shades, the amount of dye can be as much as doubled. However, the fibres cannot take in more dye than the maximum amount. It is ecological to calculate the recipe in advance and to start with slightly less dye, increasing the amount as the dyeing process continues. Different fibres absorb dye differently, which means that the same amount of dye creates a light shade in cotton and a very deep shade in polyamide. Take this into consideration when calculating how much dye you need.

Things to consider when dyeing different fibres

Wool and polyamide:

  • Good colour absorption and dark shades.
  • Hardly any traces of dye left in the finishing wash.
  • Wool has poor resistance to mechanical agitation and changes in temperature. Increase the temperature slowly and let the dye bath cool before rinsing. Wool felts easily.
  • Polyamide is used for cleaning the dyeing machine, as it absorbs all the remaining dye.

Cellulose fibres:

  • Very dark shades are difficult to achieve.
  • Particularly cotton looks remarkably darker when wet than when dry.
  • A lot of excess colour is released from the fabric in the final wash.
  • Soaking in vinegar may help set the dye slightly better.
  • Very resistant to temperature changes, good strength when wet (except for viscose).