Using techniques such as thoroughly cleaning the fabric prior to dyeing, heating the water to a simmer before adding the dye and constantly moving the fabric while dyeing improves the results when dyeing polyester. Polyester is difficult to dye but Rit DyeMore and disperse dyes such as orcocilacron adhere to it. The difficulty in dyeing exists because polyester is made from petroleum and is very similar to plastic in that both materials are hydrophobic.
Weigh the garments before dyeing in order to calculate the correct amount of dye needed. For lighter or pastel colors, less dye is needed. However, rich colors require extra dye or may need two dyeing sessions.
All garments need to be washed before dyeing in order to remove any finishes or debris on the clothing that may prevent the dye from adhering to the polyester.
When making the dye and water mixture, add 1 teaspoon of dishwashing liquid to the water to help the dye adhere to the polyester. It is also useful to test the dye water on a strip of cotton fabric first, then move on to the polyester fabric to test the color and adjust the dye mixture to get the desired result.