Crazing is an inherent characteristic of all solution-dyed acrylic fabrics and is caused by folding or creasing of the fabric during production or installation. Crazing lines appear as white lines on dark colored fabrics when front-lit, and dark lines on light colored fabrics when backlit.
The primary contributor to crazing are the resins added in the final stages of manufacturing. These resins add stiffness so the fabric lies flat during sewing, which is critical for the manufacturing process. These resins can be viewed as an industrial fabric starch with a specific end purpose.
Crazing does not affect the performance or characteristics of any acrylic fabrics — the fabric remains water repellent as well as stain and mildew resistant — and the lines will diminish over time with exposure to the elements.