Editing Knitting (section)

===Knit and purl stitches===
{{See also|List of knitting stitches}}
[[Image:Knitting red courses stockinette garter.png|thumb|Two courses of red yarn illustrating two basic fabric types. The lower red course is knit into the white row below it and is itself knit on the next row; this produces 'stockinette' stitch. The upper red course is purled into the row below and then is knit, consistent with 'garter' stitch.]]
[[File:Slipped stitch mistake.jpg|thumb|A dropped stitch, or missed stitch, is a common error that creates an extra loop to be fixed.]]

In securing the previous stitch in a wale, the next stitch can pass through the previous loop from either below or above.  If the former, the stitch is denoted as a 'knit stitch' or a 'plain stitch;' if the latter, as a 'purl stitch'. The two stitches are related in that a knit stitch seen from one side of the fabric appears as a purl stitch on the other side.

The two types of stitches have a different visual effect; the knit stitches look like 'V's stacked vertically, whereas the purl stitches look like a wavy horizontal line across the fabric. Patterns and pictures can be created in knitted fabrics by using knit and purl stitches as "[[pixel]]s"; however, such pixels are usually rectangular, rather than square, depending on the [[gauge (knitting)|gauge/tension of the knitting]]. Individual stitches, or rows of stitches, may be made taller by drawing more yarn into the new loop (an [[elongated stitch (knitting)|elongated stitch]]), which is the basis for [[uneven knitting]]: a row of tall stitches may alternate with one or more rows of short stitches for an interesting visual effect. Short and tall stitches may also alternate within a row, forming a fish-like oval pattern.

In the simplest of hand-knitted fabrics, every row of stitches are all knit (or all purl); this creates a garter stitch fabric. Alternating rows of all knit stitches and all purl stitches creates a stockinette stitch/stocking stitch pattern. Vertical stripes ([[ribbing (knitting)|ribbing]]) are possible by having alternating wales of knit and purl stitches.  For example, a common choice is 2x2 ribbing, in which two wales of knit stitches are followed by two wales of purl stitches, etc. Horizontal striping ([[welting (knitting)|welting]]) is also possible, by alternating ''rows'' of knit and purl stitches. Checkerboard patterns ([[basketweave (knitting)|basketweave]]) are also possible, the smallest of which is known as ''seed/moss stitch'': the stitches alternate between knit and purl in every wale and along every row.

Fabrics in which each knitted row is followed by a purled row, such as in stockinette/stocking stitch, have a tendency to curl—top and bottom curl toward the front (or knitted side) while the sides curl toward the back (or purled side); by contrast, those in which knit and purl stitches are arranged symmetrically (such as ribbing, garter stitch or seed/moss stitch) have more texture and tend to lie flat. Wales of purl stitches have a tendency to recede, whereas those of knit stitches tend to come forward, giving the fabric more stretchability. Thus, the purl wales in ribbing tend to be invisible, since the neighboring knit wales come forward.  Conversely, rows of purl stitches tend to form an embossed ridge relative to a row of knit stitches.  This is the basis of [[shadow knitting]], in which the appearance of a knitted fabric changes when viewed from different directions.<ref>{{cite book | last = Høxbro | first = Vivian | year = 2004 | title = Shadow Knitting | publisher = Interweave Press | location = Loveland, CO | isbn = 978-1-931499-41-5}}</ref>

Typically, a new stitch is passed through a single unsecured ('active') loop, thus lengthening that wale by one stitch.  However, this need not be so; the new loop may be passed through an already secured stitch lower down on the fabric, or even between secured stitches (a [[dip stitch (knitting)|dip stitch]]).  Depending on the distance between where the loop is drawn through the fabric and where it is knitted, dip stitches can produce a subtle stippling or long lines across the surface of the fabric, e.g., the lower leaves of a flower.  The new loop may also be passed between two stitches in the 'present' row, thus [[gather (knitting)|clustering]] the intervening stitches; this approach is often used to produce a [[smocking]] effect in the fabric.  The new loop may also be passed through 'two or more' previous stitches, producing a [[decrease (knitting)|decrease]] and merging wales together.  The merged stitches need not be from the same row; for example, a [[tuck (knitting)|tuck]] can be formed by knitting stitches together from two different rows, producing a raised horizontal welt on the fabric.

Not every stitch in a row need be knitted; some may be 'missed' (unknitted and passed to the active needle) and knitted on a subsequent row. This is known as [[slip-stitch knitting]].<ref>{{cite book | last = Bartlett | first = Roxana | year = 1998 | title = Slip-Stitch Knitting: Color Pattern the Easy Way | publisher = Interweave Press | location = Loveland, CO | isbn = 978-1-883010-32-4}}</ref>  The slipped stitches are naturally longer than the knitted ones. For example, a stitch slipped for one row before knitting would be roughly twice as tall as its knitted counterparts.  This can produce interesting visual effects, although the resulting fabric is more rigid because the slipped stitch 'pulls' on its neighbours and is less deformable. [[Slip-stitch knitting#Mosaic knitting|Mosaic knitting]] is a form of slip-stitch knitting that knits alternate colored rows and uses slip stitches to form patterns; mosaic-knit fabrics tend to be stiffer than patterned fabrics produced by other methods such as [[Fair Isle (technique)|Fair-Isle knitting]].<ref>{{cite book | last = Starmore | first = Alice | year = 1988 | title = Alice Starmore's Book of Fair Isle Knitting | publisher = Taunton | isbn = 978-0-918804-97-6}}</ref>

In some cases, a stitch may be deliberately left unsecured by a new stitch, and its wale allowed to disassemble.  This is known as [[drop-stitch knitting]], and produces a vertical ladder of see-through holes in the fabric, corresponding to where the wale had been.