The two complaints that tests prevent
Two problems account for a large share of post-purchase hijab complaints. The first is shrinkage: a jersey or viscose hijab comes out of the wash shorter and narrower, and no longer wraps the way it did. The second is color: a dark chiffon bleeds onto a white underscarf, a bright print fades in the sun, or a navy jersey rubs color onto a light coat collar. Both problems depend on fiber, construction, dye and finishing, and both can be measured before a buyer commits to bulk.
This note explains, in plain terms, what shrinkage and colorfastness tests do and how to use them in a hijab program. It does not list numeric pass limits or specific test method numbers. Those are agreed for each program with your testing lab and set out in the test plan, using standard lab test methods suited to your market.
Shrinkage: dimensional change after washing
A shrinkage test, often called dimensional stability or dimensional change, measures how much a fabric's length and width change after washing and drying under defined conditions. The lab marks a specimen, washes and dries it according to the method, measures again and reports the change in each direction.
Which fabrics need attention? Knits generally move more than wovens, and regenerated cellulose fibers such as viscose and modal can shrink more than polyester. Cotton jersey and cotton voile also shrink if not pre-treated. Crinkle fabrics are a special case, because the texture itself changes with washing. Knits can also twist after washing, a problem called spirality or torque, which makes a rectangle hijab hang unevenly; ask the lab to report it for jersey.
The practical outcome of a shrinkage result is a decision. If the change is small and acceptable, the care label can say so with confidence. If it is larger than you want, options include asking the mill for a pre-shrunk or compacted finish, cutting the hijab slightly larger to allow for it, or choosing a gentler care instruction. Each of those choices is recorded on the spec sheet.
Colorfastness: the main test types
Colorfastness tests check whether color stays in the fabric under different conditions, and whether it transfers to other materials. Results are usually reported as grades on a standard grey scale, comparing change in shade and staining against references. The table summarizes the tests most relevant to hijabs.
| Test type | What it simulates | Why it matters for hijabs |
|---|---|---|
| Colorfastness to washing | Laundering with other fabrics | Dark and bright hijabs bleeding onto underscarves |
| Colorfastness to rubbing (crocking), dry and wet | Friction against other surfaces | Dark hijabs marking collars, bags and light coats |
| Colorfastness to light | Exposure to daylight | Fading on shoulders and folds; shop window displays |
| Colorfastness to perspiration | Contact with sweat | Hijabs worn close to the neck in warm weather and sport |
| Colorfastness to water | Wetting by rain or spills | Light fabrics spotting or bleeding when wet |
| Dimensional change | Washing and drying | Shrinkage and twisting of knits |
Not every program needs every test. A plain black jersey underscarf mostly needs washing, rubbing and shrinkage results. A brightly printed modal sold for summer adds light and perspiration. A sports hijab adds perspiration and, for swim styles, the effects of chlorinated water agreed with the lab.
Where problems usually come from
- Deep shades. Black, navy, burgundy and bottle green carry more dye and are more likely to bleed or crock if washing-off after dyeing is not thorough.
- Bright prints. Some print methods and colors are more sensitive to light and rubbing; digital and screen prints can behave differently on the same base. See digital vs screen printed hijabs.
- Cellulose fibers. Viscose, modal and cotton can shrink and can show wet rubbing issues in dark colors.
- Finishes. Softeners and other finishes change hand feel and can affect results; test the fabric as it will be sold.
- Lot changes. A new dye lot of the same color is a new result. Shade and fastness can shift between lots.
Setting pass criteria in writing
Tests are only useful if everyone agrees in advance what counts as a pass. That agreement belongs in the test plan and the spec sheet, not in an email after results arrive. A good test plan lists:
- Which fabrics and colors are tested, prioritizing deep shades, prints and cellulose fibers.
- Which tests apply to each, using standard lab test methods agreed in the test plan.
- Pass criteria for each test, set by you and your lab or adviser.
- Which sample is tested: bulk or bulk-equivalent fabric with the final finish.
- What happens on a fail: rework, refinish, change of care instruction or change of fabric.
The desk sends fabric and samples to the lab you choose, records reports against each fabric and color on the spec sheet, and treats a fail as a written decision point. We do not set pass limits ourselves or issue test results. Retailers and marketplaces you sell through may also have their own test requirements, so ask them early.
Linking tests to care labels and inspection
Shrinkage and colorfastness results feed directly into the care instruction. If a dark chiffon needs to be washed separately, the label should say so; if a jersey moves more than you want after a warm wash, the label should say cold. The rules behind care labels are covered in hijab care labels. At inspection, shade is checked against the approved standard, and a quick rub check on dark colors can catch a lot that was not washed off properly; see quality control. Color approval itself is covered in hijab color matching.
Testing adds time and cost per fabric and color, so plan it into the schedule rather than adding it at the end. The MOQ and lead time page shows where testing fits, and the quote form lets you list the colors you want tested.