What is softness?
Few people realize that the most important tissue property, softness (also called handfeel by some writers), is quite different than the other properties, tensile strength, bulk, and basis weight (BW), for instance. The latter are objective, well-defined, and have easy-to-understand units. Tensile strength, for instance, is defined as force per linear area, its units are gm/cm, or oz/in; BW is weight per unit area, its units being gm/cm2, or lbs/3000ft2. A product that that is twice as strong requires twice as great a force to break it. In contrast, softness is subjective and not well defined. In fact it is not a single property but a combined one, standing for a subjective combination of several more basic properties. None of the authorities on softness agree on exactly what these properties–I call them the components of softness–are, and how they combine to yield a single measure of softness. Most agree, however, that the main components are surface smoothness, flexibility, and cus
