1. Overlap mark: a deep shade band across the full width at both ends of the fabric.

Causes: the sewn joint is too wide or too thick and is compressed after winding onto the roller; the axle is too tight, causing excessive tension; the leader cloth is too short; the shade difference between the leader cloth and the fabric is too great; the leader cloth and the fabric differ in texture.

Prevention: do not make the joint too wide; cut a few slits in the joint to avoid trapped water; adjust the tension properly so the fabric does not sag; keep the leader cloth long enough; keep the leader cloth close to the fabric in shade and texture.

2. Head-to-tail shade difference: the two ends of the fabric show different depths.

Causes: the leader cloth is not clean; dyes are not added in the order required by their properties; some dyes are dyed without a cover; temperature control is improper, with the temperature at the start of dyeing differing from later; dye liquor on the leader cloth is pressed out during winding and seeps into the fabric ends.

Prevention: keep the leader cloth clean; follow the required dyeing sequence; control the temperature consistently; check the dyeing machine and auxiliaries regularly.

3. Other common defects include color spots, streaks, creases, alkali spots, wax streaks and singeing creases. Most of them can be traced to unstable pretreatment, improper tension or temperature fluctuation. Stabilizing the pretreatment process and keeping tension and temperature uniform throughout dyeing are the most effective general measures.