Types of knitting
A modern knitting machine in the process of weft knitting.
Circular knitting on a circular needle
Flat knitting. The loops on the metal needle are the active stitches, and the yarn coming out of the knitting on the right is the working yarn. Flat knitting versus circular knitting
Main articles: Circular knitting and Flat knitting
Circular knitting (also called "knitting in the round") is a form of knitting that creates a seamless tube. Knitting is worked in rounds (the equivalent of rows in flat knitting) in a spiral. Originally, circular knitting was done using a set of four or five double-pointed knitting needles. Later, circular needles were invented. A circular needle resembles two short knitting needles connected by a cable between them. Flat knitting, on the other hand, is used, in its most basic form, to make flat, rectangular pieces of cloth. It is done with two straight knitting needles and is worked in rows, horizontal lines of stitches.
Circular knitting is employed to create pieces that are circular or tube-shaped, such as hats, socks, mittens, and sleeves. Flat knitting is usually used to knit flat pieces like scarves, blankets, afghans, and the backs and fronts of sweaters.
There is also such a thing as finger knitting. It is not done like on needles, it is done on your fingers. This produces a tube-like piece.
Felting is a technique for joining wool fibers. The finished product is put in a hot wash and agitated until it has shrunk. The end result is typically smaller. Bags, mittens, socks and hats are just a few ideas of items that could be felted.
 History and culture
Main article: History of knitting
The word is derived from knot, thought to originate from the Dutch verb knutten, which is similar to the Old English cnyttan, to knot.
This woman is knitting at a coffee shop, which is often done in a group of other knitters. Although knitting may have had a reputation as hobby one does alone, it is becoming more and more of a social activity. Knitting guilds and other knitting groups or knitting clubs are becoming exceedingly popular.One of the earliest known examples of knitting was finely decorated cotton socks found in Egypt in the end of the first millennium AD. The first knitting trade guild was started in Paris in 1527.  With the invention of the knitting machine, however, knitting "by hand" became a useful but non-essential craft. Similar to quilting, spinning, and needlepoint, knitting became a social activity.
Hand-knitting has gone into and out of fashion many times in the last two centuries, and at the turn of the 21st century it is enjoying a revival. According to the industry group Craft Yarn Council of America, the number of women knitters in the United States age 25–35 increased 150% in the two years between 2002 and 2004. The latest reincarnation is less about the make do and mend of the 1940’s and 50’s and more about making a statement about individuality as well as developing an innate sense of community. Additionally, many contemporary knitters have an interest in blogging about their knitting, patterns, and techniques, or joining a virtual community focused on knitting, such as Ravelry.
 Properties of knitted fabrics
Schematic of stockinette stitch, the most basic weft-knit fabricThe topology of a knitted fabric is relatively complex. Unlike woven fabrics, where strands usually run straight horizontally and vertically, yarn that has been knitted follows a loopy path along its row, as with the red strand in the diagram at left, in which the loops of one row have all been pulled through the loops of the row below it.
Because there is no single straight line of yarn anywhere in the pattern, a knitted piece can stretch in all directions. This elasticity is unavailable from woven fabrics, which only stretch along the bias. Many modern stretchy garments, even as they rely on elastic synthetic materials for some stretch, also achieve at least some of their stretch through knitted patterns.
Close-up of stockinette stitch
Close-up of reverse stockinette stitchThe basic knitted fabric (as in the diagram, and usually called a stocking or stockinette pattern) has a definite "right side" and "wrong side". On the right side, the visible portions of the loops are the verticals connecting two rows, arranged in a grid of V shapes. On the wrong side, the ends of the loops are visible, both the tops and bottoms, creating a much more bumpy texture sometimes called reverse stockinette. (Despite being the "wrong side," reverse stockinette is frequently used as a pattern in its own right.) Because the yarn holding rows together is all on the front, and the yarn holding side-by-side stitches together is all on the back, stockinette fabric has a strong tendency to curl toward the front on the top and bottom, and toward the back on the left and right side.
Stitches can be worked from either side, and various patterns are created by mixing regular knit stitches with the "wrong side" stitches, known as purl stitches, either in columns (ribbing), rows (garter, welting), or more complex patterns. Each such fabric has different properties: a garter stitch has much more vertical stretch, while ribbing stretches much more horizontally. Because of their front-back symmetry, these two fabrics have little curl, making them popular as edging, even when their stretch properties are not desired.
Different combinations of knit and purl stitches, along with more advanced techniques, generate fabrics of considerably variable consistency, from gauzy to very dense, from highly stretchy to relatively stiff, from flat to tightly curled, and so on.
Close-up of knitting Texture
The most common texture for a knitted garment is that generated by the flat stockinette stitch—as seen, though very small, in machine-made stockings and T-shirts—which is worked in the round as nothing but knit stitches, and worked flat as alternating rows of knit and purl. Other simple textures can be made with nothing but knit and purl stitches, including garter stitch, ribbing, and moss and seed stitches. Adding a "slip stitch" (where a loop is passed from one needle to the other) allows for a wide range of textures, including heel and linen stitches, and a number of more complicated patterns.
Close-up of ribbingSome more advanced knitting techniques create a surprising variety of complex textures. Combining certain increases, which can create small eyelet holes in the resulting fabric, with assorted decreases is key to creating knitted lace, a very open fabric resembling lace. Changing the order of stitches from one row to the next, usually with the help of a cable needle or stitch holder, is key to cable knitting, producing an endless variety of cables, honeycombs, ropes, and Aran sweater patterning. Entrelac forms a rich checkerboard texture by knitting small squares, picking up their side edges, and knitting more squares to continue the piece.
The appearance of a garment is also affected by the weight of the yarn, which describes the thickness of the spun fibre. The thicker the yarn, the more visible and apparent stitches will be; the thinner the yarn, the finer the texture.
Plenty of finished knitting projects never use more than a single colour of yarn, but there are many ways to work in multiple colors. Some yarns are dyed to be either variegated (changing color every few stitches in a random fashion) or self-striping (changing every few rows). More complicated techniques permit large fields of colour (intarsia, for example), busy small-scale patterns of color (such as Fair Isle), or both (double knitting and slip-stitch colour, for example).
Yarn with multiple shades of the same hue are called ombre, while a yarn with multiple hues may be known as a given colorway — a green, red and yellow yarn might be dubbed the "Parrot Colorway" by its manufacturer, for example. Heathered yarns contain small amounts of fibre of different colours, while tweed yarns may have greater amounts of different coloured fibres.
1904 illustration of knittingThere are many hundreds of different knitting stitches used by knitters. A piece of knitting begins with the process of casting on (also known as "binding on"), which involves the initial creation of the stitches on the needle. Different methods of casting on are used for different effects: one may be stretchy enough for lace, while another provides a decorative edging — Provisional cast-ons are used when the knitting will continue in both directions from the cast-on. There are various method employed to "cast on," such as the "thumb method" (also known as "slingshot" or "long-tail" cast-ons), where the stitches are created by a series of loops that will, when knitted, give a very loose edge ideal for "picking up stitches" and knitting a border; the "double needle method" (also known as "knit-on" or "cable cast-on"), whereby each loop placed on the needle is then "knitted on," which produces a firmer edge ideal on its own as a border; and many more. The number of active stitches remains the same as when cast on unless stitches are added (an increase) or removed (a decrease).
Most Western-style knitters follow either the English style (in which the yarn is held in the right hand) or the Continental style (in which the yarn is held in the left hand).
There are also different ways to insert the needle into the stitch. Knitting through the front of a stitch is called Western knitting. Going through the back of a stitch is called Eastern knitting. A third method, called combination knitting, goes through the front of a knit stitch and the back of a purl stitch.
Once the knitted piece is finished, the remaining live stitches are "cast off." Casting (or "binding") off loops the stitches across each other so they can be removed from the needle without unravelling the item. Although the mechanics are different from casting on, there is a similar variety of methods.
In knitting certain articles of clothing, especially larger ones like sweaters, the final knitted garment will be made of several knitted pieces, with individual sections of the garment knit separately and then sewn together. Seamless knitting, where a whole garment is knit as a single piece, is also possible. Elizabeth Zimmermann is probably the best-known proponent of seamless or circular knitting techniques. Smaller items, such as socks and hats, are usually knit in one piece on double-pointed needles or circular needles. (See Circular knitting.)
 Knitting materials
Main article: Yarn
A hank of wool yarn (center) is uncoiled into its basic loop. A tie is visible at the left; after untying, the hank may be wound into a ball or balls suitable for knitting. Knitting from a normal hank directly is likely to tangle the yarn, producing snarls.Yarn for hand-knitting is usually sold as balls or skeins (hanks), although it may also be wound on spools or cones. Skeins and balls are generally sold with a yarn-band, a label that describes the yarn's weight, length, dye lot, fiber content, washing instructions, suggested needle size, likely gauge, etc. It is common practice to save the yarn band for future reference, especially if additional skeins must be purchased. Knitters generally ensure that the yarn for a project comes from a single dye lot. The dye lot specifies a group of skeins that were dyed together and thus have precisely the same color; skeins from different dye-lots, even if very similar in color, are usually slightly different and may produce a visible stripe when knitted together. If a knitter buys insufficient yarn of a single dye lot to complete a project, additional skeins of the same dye lot can sometimes be obtained from other yarn stores or online.
The thickness or weight of the yarn is a significant factor in determining the gauge, i.e., how many stitches and rows are required to cover a given area for a given stitch pattern. Thicker yarns generally require thicker knitting needles, whereas thinner yarns may be knit with thick or thin needles. Hence, thicker yarns generally require fewer stitches, and therefore less time, to knit up a given garment. Patterns and motifs are coarser with thicker yarns; thicker yarns produce bold visual effects, whereas thinner yarns are best for refined patterns. Yarns are grouped by thickness into six categories: superfine, fine, light, medium, bulky and superbulky; quantitatively, thickness is measured by the number of wraps per inch (WPI). The related weight per unit length is usually measured in tex or dernier.
Transformation of a hank of lavender silk yarn (top) into a ball in which the knitting yarn emerges from the center (bottom). The latter is better for knitting, since the yarn is much less likely to tangle.Before knitting, the knitter will typically transform a hank into a ball where the yarn emerges from the center of the ball; this making the knitting easier by preventing the yarn from becoming easily tangled. This transformation may be done by hand, or with a device known as a ballwinder. When knitting, some knitters enclose their balls in jars to keep them clean and untangled with other yarns; the free yarn passes through a small hole in the jar-lid.
A yarn's usefulness for a knitting project is judged by several factors, such as its loft (its ability to trap air), its resilience (elasticity under tension), its washability and colorfastness, its hand (its feel, particularly softness vs. scratchiness), its durability against abrasion, its resistance to pilling, its hairiness (fuzziness), its tendency to twist or untwist, its overall weight and drape, its blocking and felting qualities, its comfort (breathability, moisture absorption, wicking properties) and of course its look, which includes its color, sheen, smoothness and ornamental features. Other factors include allergenicity; speed of drying; resistance to chemicals, moths, and mildew; melting point and flammability; retention of static electricity; and the propensity to become stained and to accept dyes. Different factors may be more significant than others for different knitting projects, so there is no one "best" yarn. The resilience and propensity to (un)twist are general properties that affect the ease of hand-knitting. More resilient yarns are more forgiving of irregularities in tension; highly twisted yarns are sometimes difficult to knit, whereas untwisting yarns can lead to split stitches, in which not all of the yarn is knitted into a stitch. A key factor in knitting is stitch definition, corresponding to how well complicated stitch patterns can be seen when made from a given yarn. Smooth, highly spun yarns are best for showing off stitch patterns; at the other extreme, very fuzzy yarns or eyelash yarns have poor stitch definition, and any complicated stitch pattern would be invisible.
The two possible twists of yarnAlthough knitting may be done with ribbons, metal wire or more exotic filaments, most yarns are made by spinning fibers. In spinning, the fibers are twisted so that the yarn resists breaking under tension; the twisting may be done in either direction, resulting in an Z-twist or S-twist yarn. If the fibers are first aligned by combing them, the yarn is smoother and called a worsted; by contrast, if the fibers are carded but not combed, the yarn is fuzzier and called woolen-spun. The fibers making up a yarn may be continuous filament fibers such as silk and many synthetics, or they may be staples (fibers of an average length, typically a few inches); naturally filament fibers are sometimes cut up into staples before spinning. The strength of the spun yarn against breaking is determined by the amount of twist, the length of the fibers and the thickness of the yarn. In general, yarns become stronger with more twist (also called worst), longer fibers and thicker yarns (more fibers); for example, thinner yarns require more twist than do thicker yarns to resist breaking under tension. The thickness of the yarn may vary along its length; a slub is a much thicker section in which a mass of fibers is incorporated into the yarn.
The spun fibers are generally divided into animal fibers, plant and synthetic fibers. These fiber types are chemically different, corresponding to proteins, carbohydrates and synthetic polymers, respectively. Animal fibers include silk, but generally are long hairs of animals such as sheep (wool), goat (angora, or cashmere goat), rabbit (angora), llama, alpaca, dog, cat, camel, yak, and muskox (qiviut). Plants used for fibers include cotton, flax (for linen), bamboo, ramie, hemp, jute, nettle, raffia, yucca, coconut husk, banana trees, soy and corn. Rayon and acetate fibers are also produced from cellulose mainly derived from trees. Common synthetic fibers include acrylics, polyesters such as dacron and ingeo, nylon and other polyamides, and olefins such as polypropylene. Of these types, wool is generally favored for knitting, chiefly owing to its superior elasticity, warmth and (sometimes) felting; however, wool is generally less convenient to clean and some people are allergic to it. It is also common to blend different fibers in the yarn, e.g., 85% alpaca and 15% silk. Even within a type of fiber, there can be great variety in the length and thickness of the fibers; for example, Merino wool and Egyptian cotton are favored because they produce exceptionally long, thin (fine) fibers for their type.
A single spun yarn may be knitted as is, or braided or plied with another. In plying, two or more yarns are spun together, almost always in the opposite sense from which they were spun individually; for example, two Z-twist yarns are usually plied with an S-twist. The opposing twist relieves some of the yarns' tendency to curl up and produces a thicker, balanced yarn. Plied yarns may themselves be plied together, producing cabled yarns or multi-stranded yarns. Sometimes, the yarns being plied are fed at different rates, so that one yarn loops around the other, as in bouclé. The single yarns may be dyed separately before plying, or afterwards to give the yarn a uniform look.
The dyeing of yarns is a complex art. Yarns need not be dyed; or they may be dyed one color, or a great variety of colors. Dyeing may be done industrially, by hand or even hand-painted onto the yarn. A great variety of synthetic dyes have been developed since the synthesis of indigo dye in the mid-19th century; however, natural dyes are also possible, although they are generally less brilliant. The color-scheme of a yarn is sometimes called its colorway. Variegated yarns can produce interesting visual effects, such as diagonal stripes; conversely, a variegated yarn may frustrate an otherwise good knitting pattern by producing distasteful color combinations.
 Knitting tools
 Knitting needles
Main article: Knitting needle
The process of knitting has three basic tasks: (1) the active (unsecured) stitches must be held so they don't drop; (2) these stitches must be released sometime after they are secured; and (3) new bights of yarn must be passed through the fabric, usually through active stitches, thus securing them. In very simple cases, knitting can be done without tools, using only the fingers to do these tasks; however, knitting is usually carried out using tools such as knitting needles, knitting machines or rigid frames. Depending on their size and shape, the rigid frames are called knitting boards, knitting rings (also called knitting looms) or knitting spools (also known as knitting knobbies, knitting nancies, or corkers). Other tools are used to prepare yarn for knitting, to measure and design knitted garments, or to make knitting easier or more comfortable.
Knitting needles in a variety of sizes (US 2, 4, 5, 6, 7, 8, 9, 10, 11, 13 and 15 from the bottom). The US size 7 and 15 needles are bamboo and wood, respectively, whereas the others are aluminum. Having a smoother surface, metal needles tend to produce faster knitting but stitches are more likely to slide off by accident.There are three basic types of knitting needles (also called "knitting pins"). The first and most common type consists of two slender, straight sticks tapered to a point at one end, and with a knob at the other end to prevent stitches from slipping off. Such needles are usually 10-16 inches long but, due to the compressibility of knitted fabrics, may be used to knit pieces significantly wider. The most important property of needles is their diameter, which ranges from below 2 mm to 25 mm (roughly 1 inch). The diameter affects the size of stitches, which affects the gauge of the knitting and the elasticity of the fabric. Thus, a simple way to change gauge is to use different needles, which is the basis of uneven knitting. Although knitting needle diameter is often measured in millimeters, there are several different size systems, particularly those specific to the United States, the United Kingdom and Japan; a conversion table is given at knitting needle. Such knitting needles may be made out of any materials, but the most common materials are metals, wood, bamboo, and plastic. Different materials have different frictions and grip the yarn differently; slick needles such as metallic needles are useful for swift knitting, whereas rougher needles such as bamboo are less prone to dropping stitches. The knitting of new stitches occurs only at the tapered ends, and needles with lighted tips have been sold to allow knitters to knit in the dark.
Double-pointed knitting needles usually come in sets of four (US size 1, on right) or five (US size 8, on left).The second type of knitting needles are straight, double-pointed knitting needles (also called "dpns"). Double-pointed needles are tapered at both ends, which allows them to be knit from either end. Dpns are typically used for circular knitting, especially smaller tube-shaped pieces such as sleeves, collars, and socks; usually one needle is active while the others hold the remaining active stitches. Dpns are somewhat shorter (typically 7 inches) and are usually sold in sets of four or five.
Circular knitting needles in three different lengths and sizes. The tips of the outermost, longest one is US size 5 and chrome-plated for speed, whereas the innermost tips are wood and US size 15; the middle red metal tips are US size 9.Cable needles are a special case of dpns, although they usually are not straight, but dimpled in the middle. Cable needles are typically very short (a few inches), and are used to hold stitches temporarily while others are being knitted. Cable patterns are made by permuting the order of stitches; although one or two stitches may be held by hand or knit out of order, cables of three or more generally require a cable needle.
The third needle type consists of circular needles, which are long, flexible double-pointed needles. The two tapered ends (typically 5 inches (130 mm) long) are rigid and straight, allowing for easy knitting; however, the two ends are connected by a flexible strand (usually nylon) that allows the two ends to be brought together. Circular needles are typically 24-60 inches long, and are usually used singly or in pairs; again, the width of the knitted piece may be significantly longer than the length of the circular needle. Special kits are available that allow circular needles of various lengths and diameters to be made as needed; rigid ends of various diameters may be screwed into strands of various lengths. The ability to work from either end of one needle is convenient in several types of knitting, such as slip-stitch versions of double knitting. Circular needles may be used for flat or circular knitting.
The Guinness World Record for Knitting with the Largest Knitting Needles
The current holder of this title is Julia Hopson  of Penzance in Cornwall. Julia knitted a square of ten stitches and ten rows in stockinette stitch using knitting needles that were 6.5 centimeters in diameter and 3.5 meters long.
Some ancillary tools used by hand-knitters. Starting from the bottom right are two crochet hooks, two stitch holders (quasi-safety pins), and two cable needles in pink and green. On the left are a pair of scissors, a yarn needle, green and blue stitch markers, and two orange point protectors. At the top left are two blue point protectors, one on a red needle.Various tools have been developed to make hand-knitting easier. Tools for measuring needle diameter and yarn properties have been discussed above, as well as the yarn swift, ballwinder and "yarntainers". Crochet hooks and a darning needle are often useful in binding off or in joining two knitted pieces edge-to-edge. The darning needle is used in duplicate stitch (also known as Swiss darning), while the crochet hook is also essential for repairing dropped stitches and some specialty stitches such as tufting. Other tools are used to prepare specific ornaments include the pompom tree for making pompoms conveniently. For large or complex patterns, it is sometimes difficult to keep track of which stitch should be knit in a particular way; therefore, several tools have been developed to identify the number of a particular row or stitch, including circular stitch markers, hanging markers, extra yarn and counters. A second potential difficulty is that the knitted piece will slide off the tapered end of the needles when unattended; this is prevented by "point protectors" that cap the tapered ends. Another problem is that too much knitting may lead to hand and wrist troubles; for this, special stress-relieving gloves are available. Finally, there are sundry bags and containers for holding knitting, yarns and needles.
Industrially, metal wire is also knitted into a metal fabric for a wide range of uses including the filter material in cafetieres, catalytic converters for cars and many other uses. These fabrics are usually manufactured on circular knitting machines that would be recognised by conventional knitters as sock machines.
Knitting in advertising
In the UK the Nestlé company advertised their popular breakfast cereal "Shreddies" on Television as being "Knitted by Nanas". The advert takes the viewer into a mythical Shreddies factory where we see how the product is really made – each piece of cereal is knitted by a Nana. The advert goes on to explain that it isn’t easy to knit the product's great taste because Shreddies need a Nana’s touch. In between explaining the intricacies that are involved, chatting Nanas get berated by the lead Nana, Betty.
Knitting as graffiti
In the past few years, a practice called yarn bombing, or the use of knitted or crocheted cloth to modify and beautify one's (usually outdoor) surroundings, emerged in the U.S. and spread worldwide. Yarn bombers sometimes target existing pieces of graffiti for beautification.
Knitting garments for free distribution to others has become common practice among knitting groups. Girls and women knit socks, sweaters, scarves, mittens, gloves, and hats for soldiers in Crimea, the American Civil War, and the Boer Wars; this practice continued in both world wars and Korea, and continues for soldiers in Iraq and Afghanistan. In the historical projects, yarn companies provided patterns approved by the various branches of the armed services; the modern projects usually entail the knitting of helmet liners; the liners provided for soldiers must be of 100% worsted weight wool.
One of the most successful modern projects has been the chemo-cap project, started in Nazareth, Pennsylvania in 2002 in memory of a woman who died of uterine cancer. The chemo cap project, and other related projects such as the Headhuggers, No Hair Day project, provide caps and head coverings for chemotherapy patients. Like the helmet liner projects, yarn companies offer free patterns; fiber must be 100% cotton or acrylic, and machine washable.