Red hoodie: dye bleed and shrinkage
A Year 11 student is making a hoodie for a school market day. The body is 100% cotton jersey in dark red; the drawcord is white cotton. The pattern was cut from unwashed fabric because the student had limited time. After sewing, they wash the hoodie in a 40°C machine wash to remove tailor's chalk and marker. The red dye bleeds onto the white drawcord, and the body shrinks 6% in length. The market day is in one week; the student has 0.5 m of the red fabric left and a spare white drawcord. The care label on the fabric bolt said 'cool hand wash only', but the student did not read it. The hoodie is otherwise well sewn, with even seams and a good fit before washing.
1. Explain the two faults - dye bleed and shrinkage - using the properties of cotton and the process used.
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Cotton is a hydrophilic fibre: it absorbs water, swells, and relaxes internal strains when washed, so a jersey can shrink several percent. The 6% length loss is consistent with washing an unshrunk cotton jersey in warm water. Dye bleed happened because the red fabric still contained unfixed dye. In warm water, the dye molecules have enough energy to leave the fibre and migrate; the white cotton drawcord absorbed them. The 40°C wash increased both effects. If the fabric had been pre-washed before cutting, the shrinkage would have occurred before the garment was sewn, and any excess dye would have been removed. The process choice - cutting first and washing the finished garment - caused both faults to appear at the worst time.
2. What can be done to make the existing hoodie saleable, and what trade-offs are involved?
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First, re-wash the hoodie in cold water with a colour catcher to remove loose dye; this is low risk and may reduce further bleeding. The white drawcord is likely permanently stained, so replace it with the spare; that is quick and cheap. To recover length, re-wet the hoodie and block it to the pattern measurements, then dry flat; some of the 6% may come back, but not all. If it is still too short, add a hem band from the 0.5 m of red fabric. Trade-off: the hem band changes the design and uses the remaining fabric, but it keeps the garment wearable. Replacing the drawcord hides the visible fault but does not fix the dye in the body. The garment may still bleed in future washes, so it should be sold with a cold-wash label.
3. How should the next hoodie be made differently?
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Pre-wash the red cotton jersey in the same way the customer will wash it, usually cold or at 30°C, and dry it before cutting. That stabilises the shrinkage. Test a small swatch for colourfastness by rubbing it and washing it with a white cloth; if dye transfers, treat the fabric with a fixative or choose a different fabric. Use a removable or dyed drawcord, or wash the drawcord separately. Sew a test seam and wash it to check for puckering. Finally, include care instructions and allow extra length in the pattern to cover any residual shrinkage. These steps cost time before cutting but prevent the need to repair or remake the finished garment.