The judgment of the warp and weft directions of woven fabrics is mainly based on the fabric edge, yarn specifications, organizational structure, and characteristic marks left during processing, and can also be combined with the front and back of the fabric for judgment.

1. Identify based on the fabric edge

The yarn parallel to the edge of the fabric is the warp yarn, and the yarn perpendicular to the edge of the fabric is the weft yarn. So the direction parallel to the fabric edge (i.e. the length direction of the fabric) is called the warp direction, and the direction perpendicular to the fabric edge (i.e. the width direction of the fabric) is called the weft direction.

2. Based on the extensibility of the fabric

Due to the constant tensile stress in the warp direction during weaving and dyeing and finishing processes, the parallelism of warp yarns is generally better than that of weft yarns. When stretching the fabric with force, the warp extensibility is poor, while the weft extensibility is good (except for warp and weft double elastic fabrics). If the yarn is split, it can be clearly seen that the weft yarn is bent and the warp yarn is relatively straight.

3. Identify based on floral features

Strip fabrics generally have stripes oriented in the warp direction; Rectangular grid fabric is generally oriented along the longitudinal direction; The smooth and harmonious visual effect of the pattern is judged by the appropriate position of latitude and longitude.

4. Identification based on fabric organization

The diagonal angle of twill fabric is greater in the warp direction and smaller in the weft direction.

The front floating yarn direction of warp satin fabric is warp direction, and the front floating yarn direction of weft satin fabric is weft direction.

5. Identify based on yarn structure and characteristics

In general, the warp density of a fabric is greater than the weft density, so the side with higher density is the warp yarn (warp) and the side with lower density is the weft yarn (weft).

When the density of warp and weft yarns is different, the thinner ones are generally the warp yarns (in the warp direction), and the thicker ones are the weft yarns (in the weft direction); If there is a system of yarns in a fabric with multiple different linear densities, this direction is the warp direction; If there is a system of colored yarns in the fabric, this direction is the weft direction. Generally, the warp twist is greater than the weft twist. When there is a set of stranded yarns in the fabric, the stranded yarns are usually the warp yarns and the single yarns are the weft yarns.