KES

Definition and Overview

KES, also called the Kawabata Evaluation System, is a method for objectively evaluating hand feel by measuring the mechanical and surface properties of fabric. In general, KES-FB refers to the measurement system used to evaluate fabric hand feel.

It quantifies firmness, resilience, smoothness, and fullness, which are difficult to share through tactile sensory evaluation alone, and is used as supporting information when comparing materials in material development, fabric selection, and quality control.

Characteristics That Can Be Evaluated

KES measures properties such as tensile, shear, bending, compression, surface friction, and surface roughness. These are factors related to ease of movement when worn, drape, firmness or softness when touched, and surface smoothness.

The measured values do not determine quality on their own. Even with the same values, suitability varies depending on the silhouette and wearing feel of the intended product, such as shirts, jackets, and coats.

• Bending properties are a guide to how easily fabric bends and its firmness.
• Shear properties relate to how fabric follows deformation in the diagonal direction.
• Compression properties relate to changes in thickness and fullness.
• Surface properties are factors for capturing frictional feel and surface unevenness.

Main Applications

KES is used when developing materials to get closer to the intended hand feel, checking differences between fabric samples and mass-produced items, and comparing multiple candidates. It is especially useful for evaluating apparel fabrics where tailoring appearance and wearing feel are important.

Season and item type are not determined by KES measurement results alone. For spring and summer, lightness and skin separation are considered, while for fall and winter, fullness and heat retention are also considered, but heat retention, breathability, and water absorption are confirmed by other tests as needed.

Selection and Handling Notes

When selecting fabric, check KES data together with fabric weight, density, blend ratio, thickness, appearance, and sewing tests. To compare materials in a state close to the intended use, it is important to use samples after finishing processes such as dyeing, brushing, and resin finishing.

KES is not a test that directly determines shrinkage, wash durability, color fading, or seam puckering. If washing or pressing may change the hand feel, in addition to comparing measurements before and after washing, conduct shrinkage tests and prototype sewing.

In sewing, fabrics with greatly different bending and shear properties will behave differently in gathering, shape formation by pressing, seam slippage, and seam shrinkage. Use the numerical data as shared information in the specification sheet and confirm sewing conditions with the actual item.

Differences from Similar Terms

Hand feel is the overall sensation experienced when looking at or touching fabric. KES is an evaluation system for measuring the physical properties related to that hand feel with instruments and comparing them numerically, and it differs from the term that expresses hand feel itself.

Drape refers to the property of fabric hanging under its own weight. KES bending and shear properties are useful for studying drape, but drape itself is also affected by shape and weight.

Frequently Asked Questions