Linen is a composite fibre obtained from the bast of Linum usitatissimum (flax) and 70% of it is cellulose.
Like all bast fibres, linen has an average length of elementary fibres ranging from 20 to 30 mm, and its fineness is around 20 to 30 microns, the fibre has a polygonal cross section.
The number of fibres present in the bark of a single plant can vary from 20 to 50.
Linen has a tenacity of about 6-7 gram/denier and has a recovery rate of 12%. Linen fibres crease easily and do not stretch. Flax fibres are contained in the inner bark, commonly known as phloem. To extract the dried stems, they must be left to soak for a few days in water basins. A faster method involves subjecting the stems to water vapour or special bacteria: the substances that bind the fibres together decompose and dissolve, thereby releasing the fibres. This process is called Retting.
The stems are then left to dry, before being subjected to braking by means of hammers, operated mechanically or by hand, which crush and grind the woody part. The next step is scutching, which removes any woody debris and separates the fibres. The raw flax is then heckled to separate the long fibres from the short and broken fibres, also called the tow. This overall process is called dressing.
As it is quite a rigid fibre, the garments take on a wrinkled look, which is one of the main distinguishing features.