The number of warp and weft threads per each square cm or inch of cloth, counted through a specially calibrated magnifying disc. The convention of fabric measurement is ‘warp before weft’ so that a given dimension of 20/24 means that there are 20 warp threads and 24 weft threads per square centimetre. Thread counts might be considered excessive information, but it is an important factor – it’s a basic definition of the fabric structure, and shows the quality of the weave – a high count invariably indicates a finely woven cloth.
In day to day life it’s particularly useful to understand bedlinen – fabric that needs to take a lot of hard wear. We’re looking for a tightly woven fabric that is soft against the skin, absorbent, yet hardwearing and firm enough that it can be laundered often and pressed to a fresh crispness, before it softens. For example, if fabric is to qualify as percale, it must have at least 200 threads per sq. inch, and top quality bedding such as that from Frette can have a thread count up to 600. The real point is that in order to get 200, or even 600, threads into the square inch, the yarn must be of the very finest quality; only the most expensive long staple cotton can be used for the highest calibre cloth.
Thread counts are often quoted as the maxim, but it is not a straightforward guide and is open to abuse. Each thread is made up and spun (see spinning) with a number of ply– and sometimes it is the number of ply rather than the number of threads that is counted. Cloth woven with three ply thread will inevitably have a lower true thread count than that woven with a single ply, and a square inch of cloth with 200 ply is nowhere near as fine a cloth than one with 200 threads. When you hold cloth in you hand you can feel its quality without necessarily needing to know its thread count.