Things You'll Need
Working with fabric dye can be tricky, especially when after the project is complete, dye continues to bleed out of the item. You can help prevent dye from spreading by making it more colorfast. Though not all fabrics, especially man-made and chemically treated options, can be made colorfast; you can help to keep dye bleeding under control.
Work with natural fibers, such as cotton, when dyeing items. Natural fibers tend to have a higher degree of colorfastness in comparison to man-made fibers that have been chemically treated and thus are prone to bleeding of dye when wet.
After dyeing fabric, use 1 cup of white vinegar in the final rinse of laundering the fabric to help set the dye. This increases the colorfastness of the dye.
Use 1 cup of table salt in the beginning cycle of laundering to further help set the dye, thus increasing the colorfastness of the dye. Know that you will need to add salt to the laundry or washing method of the fabric every time, as salt is not a permanent solution and the process will need to be continually repeated.
Choose colorfast or permanent dye to start with, to help stave off bleeding when the item gets wet.
Launder freshly dyed items separate from other items until you are sure no more color is bleeding out. To test, stop your washing machine after the wash cycle and look inside to see if the water color has changed do to dye leakage.