Patternalia

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A Crash Course in Pattern: The basics

Pattern Lingo

At an imaginary cocktail party of pattern experts, you'd find two cliques with not much in common beyond a penchant for strange eyewear: designers and mathematicians. Below are some terms you'd need to mingle with each group successfully (and impress the paisley pants off everyone).

Start at the sparkling punch bowl, where designers are handing around silver cups of same. This group will warm up our pattern party, eventually passing the baton to the mathies. Designers with a yen for patterns tend to specialize in textile or wallpaper design, or the general category that includes both, surface design — that is, the creation of proprietary patterns that a corporate client can splash onto any surface, from smartphone cases to wrapping paper. Designers start patterns by choosing a motif, figure, or unit — all synonyms for the repeated element or subject of a pattern.

Next one chooses a network(also called a grid or net lines): a repeating combination of curved or straight lines, the (usually invisible) skeleton upon which a pattern is built. Let's imagine sketching a grid on a paper tablecloth next to the designers' punch bowl. The most popular networks are either a grid of squares(resembling a tic-tac-toe board) or brick (squares shifted such that the vertical lines between columns don't line up). A brick network turned ninety degrees is called a half-drop. A diamond network looks just like squares, but on a diagonal. A network of triangles will use equilateral triangles but not always. Networks of hexagons and scales evoke honeycombs and fish, respectively. An ogee network completes this collection of grid types. Ogee lines are wavy; you can think of ogee as the gentler-proportioned cousin of the diamond or square pattern. Networks more complex than these are often built by dividing up a circle, a particularly rich trope in Islamic pattern-work. It's also possible to make a pattern's effect more complex by interlacing the figures and net lines. But this is only surface frippery: Peer past undulating details and the structure underneath should shine through.

Now comes placement of a figure onto a network, which defines the interval between figures. If the figures are crammed together, with little empty (or negative) space between them, the pattern might qualify as a diaper. (The etymological link between this kind of dense patterning and Junior's nappies isn't clear.) Diaper patterns appear frequently in backgrounds of medieval heraldic devices. As the female designers pat their lipsticked lips repeatedly on cocktail napkins, the interlacing figures (lips) produce an ersatz form of diapering.

Pattern designers also talk frequently of specific effects, like a figure-ground reversal: where the figure and background are equally sized and therefore easily confused with each other. (A chessboard or equally spaced stripes qualifies as a simple figure-ground reversal.) When you superimpose a second pattern on top of an existing pattern, that's called a countercharge. Some pattern effects relate to textile or printing processes, like resist-dying, in which you trace a pattern onto fabric with wax, dip the fabric in dye, then peel away the wax. (Other resist methods or shibori involve pleating, clamping, tying, or wrapping.) Moiré refers to overprinting of a pattern onto itself at a not-perfect angle, so the pattern appears to strobe. A pattern consisting of a gradually shaded single color has its own name, ombré.

By now the designers are deep in their cups, puppy-piling in an ecstasy of scarves. So let's swing wide the doors to our second group of pattern fans, the mathematicians. This crowd beelines it to the appetizer table, where they get busy arranging pigs-in-blankets to illustrate their own pattern lingo.

When geometricians (math types who specialize in geometry) think of patterns, they're most often concerned with the question of symmetry, or regularity of elements. Let's start with arranging those figures on a plane, à la the pigs-in-blankets on a paper plate. Spearing a toothpick into the center of the plate allows you to explore rotational symmetry. Picture two pigs laid directly across from each other, an inch away from a toothpick. Add another pig, and to maintain rotational symmetry you'd need to nudge the pigs to two, ten, and six o'clock, respectively, each an inch from the toothpick. The three little piggies are now symmetrically rotating around a central point, the toothpick, an example of 3-rotational symmetry. Rotational symmetries can climb higher in number the more pigs we add.

Reflectional symmetry happens when you introduce a line: Picture a celery spear laid horizontally on the plate. Figures (still pigs-in-blankets) will reflect themselves across the line, as if the celery were a mirror. Rotational and reflectional symmetries are collectively known as point symmetries, because each revolves around a fixed point. You can also combine rotational with reflectional symmetry. Known as dihedral symmetry, that's when the lines of reflection intersect at a central point of rotation. A daisy's petals makes a handy illustration of a dihedral symmetry: Each long petal is a reflectional symmetry, and all the petals rotate around the flower's central point.

Patterns can also grow by dilation: the figures repeat identically, but grow larger or smaller along an axis. Dartboards, waves of increasing size, snail shells, and sunflowers all demonstrate dilation symmetries of different kinds.

That maxes out the basics of planar geometry, symmetry, and pattern. But if you're ready to hit the harder stuff, head over to the Advanced Patterns After-party on page 118. (That slightly twitchy egghead will show you the way.)

Your Textile History Cribsheet

Patterns & textiles: Like PB&J

Patterns have been spread across every possible surface: painted on rocks, shells, canvas, and pottery; carved into wood, clay, and marble; printed onto manuscript sheets, museum posters, and Phish T-shirts; and beamed out as screensavers and mobile phone wallpapers. But any history of patterns — even an unconventional one — bumps into textiles more often than any other surface.

Why? A few reasons. Textiles carry pattern in a format that's portable, therefore tradeable across oceans and steppes; they are historically tricky to produce, therefore rewarding of technological innovation; they are intimate because worn on the body. All of these factors made textiles a perfect vehicle for capitalistic product-lust and keeping- up-with-the-Joneses anxiety. Textile history is considered by many historians a fine proxy for the history of all industrial technology. One scholar argues that advances in textile production were "literally the software linings" of advances that drove the Industrial Revolution and our current era of "capitalism, speed, and abstract thinking."

To appreciate the stories of patterns most often associated with cloth — camouflage, paisley, plaid, gingham, the list goes on — it helps to feel conversant in the basic jargon and history of textiles. The following will equip you with convincing patter, should you stumble into a rabid knitting circle or a convention of textile historians.

Textiles 1-2-3

Setting aside animal-skin textiles, making most fabrics involves three steps: sourcing the raw fabric-stuff, turning it into a continuous thread, and then binding those threads into fabric. Adding color can happen after any of these steps, depending on the particular effect you're going for.

Step one — sourcing the raw material for fabric — can take myriad forms: gathering loose animal fur from shrubs, shearing an animal, gutting an animal and using its (cleaned-up) sinews, harvesting plant fibers or bark. Step one might also contain sub-steps to soften the fibers, like boiling, retting (breaking fibers down by moisture), sun-drying, or beating, as well as carding(combing to remove debris and align fibers in the same direction). Eli Whitney's cotton gin mechanized carding in 1794.

Step two, making thread, has often involved twisting. This super-simple binding method increases the thread's strength by diverting some of its tensile load into lateral pressure. Holding a supply of raw material on a distaff, you pull while twisting; the resulting thread gets wound around a spindle. In its simplest form, this is called draft spinning. You can spin thread just by rubbing fibers along your thigh or between your fingers, but a spinning wheel accelerates the pace considerably. (This gadget was invented between 500 B.C.E. and 700 B.C.E.) Multiple spinning wheels speeds things up still further, as does a mechanical power source. James Hargreaves' spinning jenny (circa 1764) produced a ton of thread with multiple spindles and hand power; Samuel Compton created more durable threads with more rapid machine power in 1779.

Sometimes you can skip step two if the raw material is already pliable and thread-like enough to manipulate. Felt, for instance, requires no thread-spinning. To make felt, first get some raw puffs of wool and degrease them. Second, knot the fibers permanently together. Two popular methods involve laying the fibers in cotton cloth, binding them tightly into a sausage, and then boiling it, or wetting the fibers with hot water and rolling them out, cookie-dough-like, between mats.

Step three — binding threads into a textile — was historically the slowest, most labor-intensive step and therefore a particular focus for innovators. Fabric gets made from scratch by weaving or knitting, or by a range of similar techniques like knotting, crochet, or braiding. In weaving, threads are generally held straight, whereas in knitting threads follow a meandering, looped path (called a course). Both weaving and knitting can be accomplished by hand or machine; we'll focus on weaving. The next section acquaints you with the three varieties of looms used in preindustrial weaving: backstrap, warp-weighted, and ground looms.

The Changing anatomy of Looms

Loom lingo starts here. In weaving, one thread must stay taut: That's called the warp. The weft is the moveable thread whose action around the warp creates the weave. You hold the warp threads (called ends) tense between two rods, using weights or a convenient tree, or even a backstrap (a loom, one end of which is attached to your waist). You wedge a shed rod in between the warps to create a natural shed or opening for your shuttle or bobbin; your weft thread is wound around this doohickey and passed from left to right, or right to left, through the opening of the shed. Each pass creates a pick made of one weft thread. When one pick is in place the shed is opened up with the alternate configuration of warp threads, making room for the next pick.

The most boring weave, just endless weft-warp-weft-warp with zero variation, is cutely called tabby. If warp and weft are differently colored, you'd produce a basic plaid, but that's as fancy as tabby could get. To make fancier patterns you need a way to lift only certain warps, so you could weave just around the warps that remained flat. In basic looms, you could accomplish this by wedging in a heddle rod. You'd attach multiple warps to the heddle rod with loops, allowing you to raise and lower them as a group. Last but not least is the dramatically named sword, a rod used to beat the just-woven weft tightly into place.

Let's zero in on the heddles; those were the limiting factor in how complex patterns could get. You could add more than one heddle rod, and eventually the treadle loom allowed the weaver to manipulate heddles with a foot pedal. But a hand loom bristling with too many heddles got unmanageably crowded.

Enter the drawloom, now easily a millennium old. In a drawloom each warp was inserted through a leash, a network of cords suspended over the loom. First a "flower-lasher" programmed the drawloom manually. He read the pattern instructions detailed on graph paper and tied leashes into groupings, so warps could be raised or lowered together at whatever point the instructions called for. The harness cords in the ground weave could be similarly controlled. During weaving, a "drawboy" or "drawgirl" pulled the leashes to put the pattern's program into action.

A later innovation, the dobby loom, controlled all the warp threads with a peg arrangement. Dobby looms work hand-in-hand with another key innovation, the flying shuttle. As its name suggests, the flying shuttle zipped the weft thread more rapidly through the shed, making it easier, faster, and less laborious to weave textiles wider than arms' breadth.

Enter the Jacquard loom, a major textile game-changer. It automated drawboys out of existence and morphed the "flower-lashers" into "card-cutters." In the Jacquard loom all warp threads were controlled by two overhead series of joined punch cards. One set of cards determined the ground weave; the other replaced all the raisings and lowerings of warps the drawboy once handled. Uncannily futuristic, metal Jacquard cards look exactly like the paper punch-card "programs" guys in horn-rimmed glasses fed into room-sized computers in the 1960s.

Valerie Reilly, author of The Paisley Pattern: The Official Illustrated History, explains: "Following each line of the point-paper design, the cutter would use combinations of the ten keys on the machine to cut holes in the correct places on the cards. The cards were then laced into a continuous band and passed to the weaver ready for his machine." In other words, the one-time manual program produced by the "flower-lasher" was abstracted onto metal cards, one card per shuttle pass, that could be easily copied and reused. Reuse was totally the name of the game, too, as the upfront cost of making a set of Jacquard cards was steep: It took as many as 424,000 cards to program a single design. More than any other fear-provoking innovation, it was the dreaded Jacquard loom that prompted weavers to join Ned Ludd in 1812 in industrial sabotage, destroying wool and cotton mills under cover of darkness: the original Luddites. (Fun Sartorial Aside: The word "sabotage" derives from the French word sabot, or "clog." Luddites liked to chuck their wooden shoes into mechanical looms, breaking them in spectacular style.)

Finishing a fully woven textile could involve a zillion other techniques, some of which introduced or altered the final pattern: braiding, quiltwork, appliqué, fulling (shrinking cloth to smooth its appearance), waulking (beating finished cloth to soften it), cropping(shearing excess threads, either from the front to create a velvet effect or from the reverse side), plus many others. In the preindustrial era, these tasks were backbreaking, repetitive, and dull. Scottish women, for instance, livened up the waulking necessary to finish tartan by beating the fabric in time to songs about love and heartbreak. (Too tired to give it your all? Just sit next to a woman recently wronged by her sweetheart and draft off her vim.)

Textiles Go Global

Luxury textiles had always traded globally, of course, but the Industrial Revolution accelerated and democratized this trade to a head-spinning degree. Machine weaving and knitting produced an abundance of cloth at ever-plummeting prices, with corresponding upheavals to the workforce and society. Textile printing techniques advanced, too, making it that much easier to stamp a pattern directly onto a textile's surface. (Textile printing made patterning so easy, in fact, it eventually gave rise to disposable fashions. More on these in the next section.)

A pattern's meaning often wandered as it crossed national borders. An apt case-in-point are what's commonly known as "African prints," the gorgeously clashing, geometric prints scrawled with fat black lines, as if with Sharpie markers. This category of pattern is properly called Dutch wax batik, and its story shows just how many geographically dispersed meanings can embed in a given pattern.