Always identify the fabric type before dyeing
Some fabrics do not dye at all, such as polyester and acrylics (they can only be dyed industrially), while others do not lend themselves to temperature treatment - such as wool.
Never mix material types when dyeing
Materials dye differently. You will not get the same result on different fabric types because they differ in their affinity for dyes and the temperatures at which they change shade.
Always accurately weigh the dry fabric before making the dye solution
The shade is determined by the dosage of dye. This means that the amount of dye is determined by the weight of the fabric that the dye is applied to.
First wash all fabric in hot, soapy water (whether or new or used).
Clothing contains impurities and dirt. Even new clothes contain sizing and starchy substances that facilitate its handling and treatment in manufacture. These traces adversely affect dyeing they affect the shade achieved and the levelness of the result.
Heat the dye bath slowly
A gradual increase in temperature causes a more thorough flow of dye into the fabric. A gradual increase in temperature also permits more time to agitate and stir the fabric, promoting better exposure and more level dyeing. As the temperature rises the pace of dyeing increases.
Don't underfill or over a washing machine with fabric
This will affect the dyeing process negatively.
Always fix in the dye
The hallmark of an effective dye - given good shading - is its ability to last and withstand washing. Both colour-fastness and wash-fastness are required to ensure coulours won't fade. So always carefully apply fixative according to the manufacturer's directions and don't shortcut the process.
When using a washing machine, be extra careful when weighing fabrics and dyes
Dyeing in a washing machine is convenient and quick when you have a lot of material to dye. But it has to be planned.
Always read the instructions first!
This will save you from making mistakes.