Linen and poplin are not two answers to the same question. Linen is a fibre, the one taken from the stem of the flax plant. Poplin is a weave, a particular way of crossing threads that can be carried out in more than one fibre. Anyone comparing linen vs poplin in a shirt is, in practice, comparing a linen shirt with a cotton poplin shirt, since cotton is what shirting poplin is most often made of today. Putting it that way removes most of the confusion and leaves a real and useful choice.

Poplin first. It is a plain weave, one thread over and one under, in which the lengthwise threads are fine and set closely together and the crosswise threads are slightly heavier. The result is a smooth, dense cloth with a very faint rib running across it, visible only at close range. The name is generally traced to papeline, a cloth of silk and wool once woven at Avignon. Cotton took over long ago, and cotton poplin became the standard cloth of the business shirt; in North America the same fabric is often called broadcloth. It is crisp, even and cool to the first touch.

Linen is usually a plain weave too, so the structure is not what separates them. The fibre is. Flax yields long, strong strands with very little elasticity and a slightly irregular thickness, and the yarn spun from them keeps some of that character in the form of the small thickenings known as slubs, which are explained in linen slubs. Woven, it makes a cloth that is more open than poplin, drier in the hand, matte where poplin has a slight sheen, and visibly textured. Where poplin sets out to be uniform, linen shows how it was made.

On the body the two behave differently, and heat is where the difference is felt. Poplin's close weave lies smooth against the skin, which is pleasant in a cool room; in humid weather that same closeness lets less air through, and the cloth can cling once it is damp. Linen can take up a good deal of moisture before it feels wet, and because the fibre is stiffer the cloth holds a little away from the body, so air moves beneath it. This is the practical basis of linen's reputation in summer. It does not make cotton a poor choice, and the broader comparison is made in linen vs cotton shirts for men.

Appearance is the other half, and here honesty favours poplin in one respect. Poplin presses flat and sharp. It takes a tie well, sits cleanly under a jacket, and at the end of an office day shows only fine creases at the elbow and waist. Linen creases sooner and more broadly, and no finish worth having changes that. What linen offers instead is depth: a surface that takes colour softly, softens with each wash, and looks correct in open air and strong light, where a pressed poplin shirt can look as if it has come from a meeting.

So the choice is largely one of setting. Poplin belongs with a suit and tie, in a boardroom, at a formal dinner indoors, and in cities where the air conditioning is set low. Linen belongs to heat, to travel, to terraces and boats and long lunches, and to evenings out of doors. There is a middle ground in which either will do, such as a summer office without a tie or dinner in town in June, and in that ground a long-sleeved linen shirt, pressed, under an unlined jacket is a quietly good answer.

Pieter Petros is a linen house, and the men's shirts that come closest to the role of a poplin dress shirt are the long-sleeved ones: the Bliss Linen Shirt, in six colourways including Dark Blue, Vanille and Sky Blue, and the Laos Long Sleeve Linen Shirt in Oyster, Beige Cream and Dark Blue. They are found in the PP linen shirts collection. The cloth at the centre of the collection is certified Belgian linen, and most of the shirts close with seashell buttons. A man who owns good poplin shirts already does not need to replace them. He needs the other shirt, for the half of the year and the half of his life that poplin was not woven for.

Two last points for the careful reader. Because poplin is a weave, linen poplin can exist, and cotton and linen are sometimes woven together; neither is common in shirting, and a label will say so plainly where it applies. And the two cloths ask for slightly different care. Poplin tolerates a warmer wash and a hot iron; linen is happier at 30°C and irons most easily while it is still a little damp. Looked after in that way, a linen shirt improves over the years in which a poplin one merely lasts.

Linen vs Chambray  ·  Linen vs Seersucker  ·  The Linen Shirt for Business Casual