Knitting

Knitting is a method of creating a fabric by means of pulling rows of loops of yarn through other loops with straight needles. The fabric thus created is very elastic and well-suited to the creation of garments such as socks and hats which rely on elasticity to fit the wearer comfortably.

Tools

Knitting needles can be made of a variety of materials, including wood, metal, and plastic, and come in a variety of formats. Long needles with a point at one end and a stopper at the other are usually referred to as "straights", while those with a point at each end, used for knitting tubular fabrics, are called "double-pointeds" or "dpns". A special kind of needle consists of a flexible cable with a solid, pointed portion at each end; these are called "cable needles". Some types of knitting use needles with hooks at one end, much like crochet hooks.

Needles are sized by their diameter, which is important in determining the size of the stitches they will form. The size of the stitches, known as gauge or tension, is crucial to the size of the finished object, and needles are a vital part of determining gauge.

Aside from the needles, the only required tool is the yarn itself. While wool is probably the most popular fiber for knitting, many other materials are also used. Cotton, linen, silk, and many other synthetic and natural fibers are used for various purposes. Along with fiber content, yarn can also vary in weight, from bulky yarns that produce only a stitch or so to the inch to laceweight, which, on appropriate needles, produces 20 or more stitches per inch.

Techniques

To begin knitting, one must first cast on by putting the first row of loops on the needle. There are many methods of casting on, each with characteristic strengths and weaknesses. For example, a provisional cast on is useful if the knitter wishes to pick up stitches and work in the other direction at a later point, but cannot be left alone if she later changes her mind. Long-tail cast on, by contrast, is a permanent cast on and is flexible and neat, but requires careful judgement of the length of its eponymous tail lest one run out of yarn before the required number of stitches is reached.

The basic stitch in knitting is, unsurprisingly, called the knit stitch. To form it, the knitter inserts the tip of the right needle into the first loop on the left needle from front to back¹, wraps the yarn around it, and pulls a new loop to the front. The old loop is dropped from the left needle and the process repeats until there are no loops remaining on the left needle. The purl stitch is very similar except that the right needle is inserted from back to front; a knit stitch on the front of the work is a purl stitch on the back, and vice versa².

If she is working "flat", when the knitter reaches the end of a row of loops, the work is turned so that the needle with stitches on it is in the left hand again. If the knitter continues to knit every row, a fabric called garter stitch is produced. If she purls instead, and continues to alternate knitted and purled rows, the resultant fabric is called stockinette, and is what most people envision when they think of knitting: very smooth rows and columns of V-shaped stitches on one side, with the stitches of the other being quite bumpy and hard to distinguish.

Cable needles and double-pointed needles can be used to work "in the round" instead. In this case, the knitter sets up the initial cast on so that the last stitch is immediately followed by the first. This produces a tubular fabric. The beginning of the round must be marked in some way, commonly with a stitch marker hung from the needle or with a narrow, obvious stitch pattern. A knitter who wishes to produce stockinette in the round knits every stitch of every round; alternating knit and purl rounds makes garter stitch instead.

Knitters can produce additional stitches, and make the work wider, by increasing; stitches can be removed, thus narrowing the work, by decreasing. (In fact, in older patterns decreasing is often called "narrow" instead.)

1: Some people teach left-handed knitters to knit from right to left instead, though this is generally considered inadvisable because knitting is essentially a two-handed activity and knitting right to left requires the knitter to reverse all the directions in standard patterns. However, in situations where rows are very short (such as knitting a narrow strip or when working entrelac), being able to knit "backwards" can save considerable time.

2: Because of the different orientation of the needle, some knitters' work is susceptible to a phenomenon known as "rowing out". This is caused by the tiny difference in the length of yarn necessary to circle the needle when purling as opposed to knitting, and can cause stitches on knit rows to be slightly shorter than those on purl rows. In stockinette stitch, rowing out is easily seen on both sides of the work and is considered a flaw. Knitters deal with the problem in different ways, including using a slightly smaller needle for purl rows, wrapping their yarns differently, pulling purl stitches a bit tighter, and working in the round so as to never have to purl at all.