People who have learned to shop for cotton by thread count often bring the habit to linen and are puzzled by what they find. Linen thread count figures, where they are given at all, are low: commonly somewhere between eighty and a hundred and fifty, against the several hundred advertised for cotton. The natural conclusion is that linen must be the coarser, lesser cloth. It is the wrong conclusion. The number is low for a reason that has nothing to do with quality, and it tells a buyer almost nothing about whether a linen garment is well made.

Thread count is simply the number of yarns, lengthwise and crosswise together, in one square inch of woven fabric. It became a selling point in cotton because fine cotton fibre can be spun into very thin yarn, and thin yarn can be packed densely. Flax is a different fibre. It is thicker, stiffer and far longer than cotton, and it spins into a yarn with more body. Fewer of those yarns fit into a square inch. A linen cloth with a count of a hundred and twenty may be as fine an example of its kind as a cotton with a count of four hundred is of its own.

There is a further point. A very high count is not even a desirable aim in linen. Much of what makes the cloth comfortable in heat comes from the small spaces between its yarns, which allow air to pass and moisture to leave. A linen woven as tightly as the yarn would allow would lose some of that openness and become stiff and warm. Good shirting linen is a balance: close enough to be opaque, smooth and durable, open enough to breathe. The weaver's skill lies in finding that balance, and a single number per square inch does not describe it.

What, then, should be read instead? The first measure is weight, given in grams per square metre. It says how much linen there actually is in the cloth, and it corresponds to how the garment will feel and hang. Shirting linens sit towards the lighter end of the range, linens for trousers and jackets higher. Neither light nor heavy is better in itself; a very light linen is airy and more transparent, a heavier one drapes with more authority and lasts longer at the seat and elbow. The Journal's linen weight guide goes through the range.

The second is the length of the fibre, which no label states and every hand can feel. When flax is processed, the long fibres are separated from the short. Long fibre is spun into smooth, strong, lustrous yarn; the short fibre makes a hairier, weaker yarn that is perfectly useful for other purposes and is sometimes woven into clothing regardless. Cloth made from long fibre has a clean surface, a cool dry touch and a slight sheen. It softens over the years and sheds very little.

The third is evenness. Hold the cloth to the light. Linen yarn is never perfectly regular, and the occasional thicker place, the slub, is part of its character and no defect. What you are looking for is consistency of weave: yarns evenly spaced, no thin patches, no areas where the cloth looks sparse. A well-woven linen shows a regular, calm grid with its slubs scattered at random. A poorly woven one looks uneven in density, and that unevenness is where it will wear through first.

The fourth is origin, because it is a claim that can be verified. The flax-growing belt of Western Europe, from northern France through Belgium to the Netherlands, has the climate and the long practice that the crop requires, and Belgian Linen is a registered mark for cloth woven in Belgium from European flax. A certificate is not a guarantee of taste, but it is a guarantee of fact, and it is worth more than any count. The core of the PP collection is certified Belgian linen, and the house's guide to identifying premium linen lists what to look for in the hand.

Last comes the making, which lies outside the cloth altogether. A fine linen can be let down by hurried sewing. Look at the seams from the inside: they should be enclosed and flat, with small, even stitches. Look at how the collar sits and whether the placket lies straight. Look at the buttons. PP's men's shirts, shown in the linen shirt collection, close with seashell, with walnut on the Monte-Carlo Male, and the garments across the men's linen collection are handmade in the Dubai atelier and in Belgium. None of that appears in a thread count either.

The simplest test remains the oldest. Take the cloth between finger and thumb. Good linen is cool, dry and smooth, with a quiet firmness, and it feels like something that will improve. If a seller offers a thread count for linen, it does no harm. If that is all they offer, put the number aside and go back to the cloth in your hand.

Linen Quality: The Difference Between Grades  ·  The Linen Fabric Weight Guide  ·  What Is Belgian Linen