Fundamentals of Laundry and Dyeing
This domain tests whether you can separate aqueous laundry from solvent dry cleaning and sequence a complete textile-care job.
Core rules
- Laundry uses water plus soap or detergent. Dry cleaning uses an organic solvent and suits oily soil, tailored wool, silk and some embellished garments.
- A reliable workflow is collection, inspection, marking, sorting, stain removal, washing, rinsing, hydro-extraction, drying, finishing, quality check and delivery.
- Water quality matters. Hardness from calcium and magnesium wastes soap and can grey whites. pH, iron and chlorine affect both cleaning and dyeing.
- Match temperature, time, mechanical action and chemical concentration to the fibre and soil. This is the practical version of the Sinner circle.
- Dyeing is separate from cleaning. It needs scouring, controlled dye uptake, fixation and fastness testing.
Worked example
A woollen shawl has a greasy collar and a water-soluble ink mark. Wool felts and shrinks under heat and agitation, so a hot wash is wrong. Dry clean the shawl for the grease, then treat the ink spot on a spotting table with a tested agent after checking fibre and colour. Reasoning: the fibre controls the process, and the two stains need different chemistry.
Traps that cost marks
- Treating dry cleaning as a universal stain remover. It removes oils, not sugar, salt or tannin stains.
- Using hot water on blood, egg or milk.
- Skipping marking, so garments are mixed and returned to the wrong customer.
- Ignoring water hardness when choosing soap.