Cover Factor
Cover Factor is an index that indicates how much the surface of a fabric is covered by yarn, based on yarn thickness and the density of warp and weft yarns or stitches.
Contents6 sections
Definition and Overview
Cover factor is an index of how much a fabric surface is covered by yarn, calculated by combining yarn thickness and fabric density. It is mainly used for woven fabrics, and may be handled as values in the warp direction, weft direction, and their total.
The calculation method varies depending on the yarn count system used and whether the material is woven or knitted. Even if the numerical value has the same name, it cannot be compared directly if the calculation conditions differ, so specifications should list the yarn count, density, and formula together for confirmation.
Effects on Hand and Function
In general, fabrics with a high cover factor have smaller gaps between yarns and appear more tightly constructed. Sheerness is reduced, and it is easier to achieve firmness, body, and wind resistance, while breathability and soft drape tend to decrease.
Fabrics with a low cover factor can better make use of lightness, breathability, and fabric-to-skin separation, and are suitable for a sheer appearance. However, even with the same value, luster, stiffness, sheerness, and water absorbency vary depending on the weave structure, yarn twist, fuzz, finishing, and fiber type.
- High value: easy to achieve a dense appearance, low sheerness, firmness, and wind resistance.
- Low value: easy to achieve lightness, breathability, and softness.
- The value alone does not guarantee water repellency, waterproofness, warmth retention, or strength.
Main Applications and Seasonality
A high cover factor is used for shirts, pants, jackets, outerwear, and similar items that require less wind penetration and a firm look. In high-density plain weaves and twills, finishing may be combined to adjust the performance needed for the application.
A low cover factor is suitable for spring and summer shirts, blouses, dresses, and similar items where breathability and a light appearance are important. However, suitability for an item is not determined by cover factor alone, so fabric weight, structure, sheerness, and strength should also be considered.
How to Choose and Handling Precautions
When selecting fabric, confirm the target appearance and breathability with the actual material, and compare cover factors calculated under the same conditions. Even if fabric weight and density are similar, a fabric with thick yarns set loosely and a fabric with fine yarns set at high density will differ in hand and sewability.
When the fabric shrinks through washing or finishing, the density changes and the cover condition during use also changes. In particular, for products that are washed in water, confirm shrinkage, and if necessary, perform prewashing and trial sewing before deciding the pattern and specifications.
High-density fabrics with firmness may show needle holes, puckering, and seam slippage. Select a needle size and sewing thread suited to the fabric, and test stitch pitch, thread tension, and presser foot pressure to check for surface damage and seam shrinkage.
Difference from Density
Density is an index showing the number of warp and weft yarns arranged per unit length. Cover factor takes yarn thickness into account as well, so even if density is the same, the value changes if the yarn used is different.
Cover factor is not the name of a fabric structure or material, but a design index. Also, fabric weight is a separate index that indicates weight per unit area, and a high cover factor does not necessarily mean a high fabric weight.
Frequently Asked Questions
Does a higher cover factor also mean better waterproofness?
Fabrics with a high cover factor have smaller gaps between yarns, which may contribute to wind resistance and make it harder for water droplets to pass through. However, waterproofness also depends on the material, structure, processing such as coating or lamination, and seam specifications, so it cannot be judged by the value alone.
Are cover factor and density the same?
No, they are not. Density indicates the number of yarns per unit length. Cover factor, on the other hand, is an index of the cover condition that takes yarn thickness into account in addition to density. When comparing how tightly a fabric is constructed, it is important to check both, as well as fabric weight and structure.
