Bias
Bias refers to the direction cut and laid out diagonally to the warp and weft of a woven fabric, typically at a 45-degree angle, using the textile’s stretch and drapeability.
Definition and Overview
Bias refers to a direction that is diagonal to the grain of the fabric, which is parallel to the warp and weft threads. In particular, a direction that is approximately 45 degrees to the warp or weft threads is called true bias, and is used in cutting clothing and making bias tape.
Woven fabrics generally stretch more easily in the bias direction than in the warp or weft directions, and they also conform more easily to curves. This property is used to create a sense of conformity to the body and drape.
Features
When cut on the bias, even if the textile itself does not contain any stretch material, a moderate amount of stretch can be obtained due to the diagonal deformation. It is characterized by its ability to easily conform to the body's movements and create a soft drape.
On the other hand, the bias direction is prone to stretching and changing shape when pulled, which can lead to unstable dimensions during cutting and sewing. With pattern, it's also important to note that the appearance of the pattern may change diagonally.
Main applications
Bias cutting is used in dresses, skirts, blouses, and camisoles that take advantage of drape. Bias tape, which is used to wrap curved areas such as necklines and armholes, is another typical applications that utilizes the diagonal stretch of fabric.
When finishing the edges of textile, bias tape is useful because it easily conforms to curves. However, for areas where you want to reinforce straight sections or prevent stretching, you may want to choose tape cut in the direction of the fabric grain.
- Curved edging/piping
- Facing and finishing of neckline and armholes
- Garment bodices and skirts that take advantage of draping properties
- Tape-like hardware that conforms to stretch
How to choose and precautions for handling
When using bias cutting, check the textile 's weave, thickness, drape, and diagonal stretch beforehand. Thin, slippery, and textile textile are prone to losing their shape, so pre-cutting preparation and sufficient fabric requirements are important.
In sewing, one method is to hang the cut hardware to allow it to settle before adjusting the length. In areas where seams are prone to stretching, use stay tape or interfacing as needed to avoid pulling the textile too hard during sewing.
Because the shape may change due to washing or steaming, washing and sewing tests are conducted before mass production to check for shrinkage, stretching, and seam waviness. For hardware oriented on the bias, care must be taken to prevent stretching during storage.
Differences from similar terms
The grain of the fabric refers to the direction of the warp and weft threads in a woven fabric, and the standard for cutting along that direction. Bias is a direction diagonal to the grain of the fabric, and the two are symmetrical as cutting directions.
Bias tape is a narrow piece of fabric cut on the bias. "Bias" refers to the direction and cutting method itself, while "bias tape" refers to auxiliary materials and hardware that utilize this property. While "half bias" can refer to a shallower diagonal cut than true bias, the terminology and angle usage vary depending on the context.
FAQ
Why does textile stretch when cut on the bias?
Because the warp and weft threads of a fabric are perpendicular to each other, applying force diagonally can easily change the angle between the thread. This deformation causes the fabric to feel relatively stretchy in the bias direction, even if the textile itself is not made of elastic thread. The degree of stretch varies depending on the weave, density, material, and finish.
Can bias tape be used on straight sections as well?
While it can be used, for straight edging only, a tape with less stretch in the grain direction may be more suitable. Bias tape conforms well to curves, but if pulled too tightly, it can lead to waviness and uneven stretching. Choose the tape's cutting direction and finish according to the applications.
Is the fabric requirement for bias cutting the same as for regular cutting?
They may not be the same. Because the hardware is positioned diagonally, the textile width cannot be used efficiently, and the required amount of fabric may increase. For fabrics that require textile matching or have directional patterns, you will need to allow for even more extra fabric. Always check the markings with the actual pattern and textile width.
