Lys River-Retted Long-Staple Flax Fiber Spinning for Architectural Linen

The legendary stature of Flemish linen was forged along the banks of the River Lys (Leie), which meanders through the historic flax-growing territories of northern France and West Flanders before joining the Scheldt at Ghent. Throughout the 19th and early 20th centuries, this waterway was known across the textile world as De Gouden Rivier ("The Golden River"), a name inspired both by the immense commercial wealth generated by its flax trade and the shimmering golden-blonde hue acquired by flax stalks submerged in its waters. The river possessed a rare conjunction of biochemical attributes: a slow, tranquil current that prevented mechanical damage to submerged bundles, a remarkably low concentration of dissolved lime (calcium carbonate) that preserved fiber suppleness, and a total absence of iron compounds that would otherwise oxidize and permanently stain the fibers a dull grey-black.

In historic practice, harvested flax was tied into sheaves and packed vertically into massive slatted wooden crates known as hekkens. These crates, measuring up to six meters in length, were lined with straw and weighted down with sod and stones until submerged just beneath the river surface. Over six to ten days, natural anaerobic bacteria (chiefly Clostridium felsineum) proliferated in the warm, slow-moving water, systematically fermenting and dissolving the pectinaceous middle lamella that cemented the fibrous bast bundles to the woody inner stem. The process required meticulous sensory monitoring: master retters tested stems daily by breaking them across their thumbs. When the inner wood snapped cleanly and pulled free from the intact fiber sheath without resistance, the crates were hauled ashore immediately, terminating microbial digestion before the cellulose walls themselves could be attacked.

Following retting and thorough field drying, the flax straw must undergo mechanical separation to strip away the fractured core. This begins with the "breaking" operation. In traditional Flemish mills, dried flax bundles are fed through a series of interlocking, fluted steel rollers rotating at differing speeds. As the straw passes through these corrugated nips, the inner woody stem—the shive or boon—is pulverized into tiny fragments, while the tough, pliable bast fibers flex without breaking. The key to successful breaking is maintaining strict moisture equilibrium: if the straw is too dry (below 9% moisture), the valuable outer fibers shatter; if too damp (above 15%), the shives remain gummy and cling tenaciously to the fiber ribbons.

Immediately following the breaking rollers, the fiber stricks enter the scutching turbine (zwingelmolen). The scutching machine grips the flax bundle in a continuous rubberized belt while high-speed revolving drums fitted with wooden or lightweight steel scutching blades strike the hanging stems with glancing blows. These rapid downward impacts beat out the shattered shives, allowing them to fall through collection grates beneath the machine. The scutching action separates the harvest into two distinct commercial streams: "scutched line flax," consisting of long, unbroken bundles running the full length of the stem, and "scutching tow," comprising the short, entangled fibers and waste stripped away with the shive debris. Modern scutching lines incorporate sensitive pneumatic suction systems that capture airborne dust and separate pure shive for industrial composite boards, ensuring pristine, debris-free line flax for architectural weavers.

Scutched line flax cannot be spun directly; it remains composed of coarse, overlapping fiber bundles bound by residual dried pectins. To convert these bundles into spinnable filaments, the flax must undergo hackling (hekelen)—a precision mechanical combing process. Hackling straightens the fibers, aligns them into strictly parallel ribbons, splits composite bundles into their fine elementary fiber cells, and removes any remaining tow or particulate matter. In historical workshops, hackling was performed manually by drawing handfuls of flax across wooden boards studded with hundreds of sharp, needle-like steel pins; today, fully automated continuous hackling machines perform this operation with micron-level consistency.

The hackling process is strictly progressive. The flax stricks are clamped into aluminum holders that travel horizontally along a conveyor track over pairs of vertically rotating pin sheets (hackle aprons). The fibers first encounter coarse pins (8 to 12 pins per square inch) that gently untangle the tips without causing fiber breakage. As the holders advance, the pin density progressively increases—through 16, 24, 36, and finally up to 50 to 60 pins per square inch—with pins as fine as sewing needles. By the time the flax emerges from the finest pin field, it has been transformed into a luminous, silky cascade of parallel fibers known as "dressed line." The short fibers combed out during this sequence are collected as "hackling tow," while the dressed line is graded based on fiber fineness, color uniformity, tensile tenacity, and tactile suppleness, with the highest grades reserved for wallcovering warps.

The pinnacle of flax yarn manufacturing is the wet-spinning process, an engineering innovation pioneered in the early 19th century by Philippe de Girard that revolutionized the production of ultra-fine linen. For architectural wallcoverings, where warp threads must withstand immense loom tension without snapping and provide a completely uniform, slub-free surface, wet-spinning is mandatory. The combed line flax slivers are first processed on drawing frames and roving frames to create a slightly twisted roving wound onto plastic bobbins. These bobbins are loaded onto the creels of a wet-spinning ring frame.

During spinning, the roving passes through an insulated stainless steel trough containing hot water maintained at 55°C to 65°C before reaching the drafting rollers. The elevated temperature and moisture hydrate and soften the residual hydrophobic pectins and hemicelluloses located within the middle lamella of the fiber bundles. As the softened roving enters the precision drafting zone, the individual elementary fiber cells (which average 20 to 40 millimeters in length and 15 to 25 microns in diameter) can slide smoothly past one another without tearing. The drafted fiber stream is immediately twisted by a high-speed traveler and ring spindle, compacting the fibers into a tight, dense, circular cross-section. As the yarn cools and dries, the softened natural pectins re-solidify, effectively acting as an intrinsic botanical adhesive that bonds the fibers together. This produces an exceptionally smooth, lustrous yarn with superior tensile strength and virtually zero surface fuzziness, ready to be warped for the most intricate Flemish Jacquard wall textiles.