Slip-stitch knitting

Family of knitting techniques

Slip stitch knitting is a family of knitting techniques that uses slip stitches to make multiple fabrics simultaneously, to make extra long stitches, and/or to carry over colors from an earlier row.

In the basic slip stitch the stitch is passed from the left needle to the right needle without being knitted. The yarn may be passed invisibly behind the slipped stitch (wyib="with yarn in back") or in front of the slipped stitch (wyif="with yarn in front"), where it produces a small horizontal "bar". The wyif slipped stitch is less common,
although several knitting patterns use it to produce a visual effect like woven cloth. Alternatively, the yarn can be "tucked", i. e., made into a yarn over that is knitted together with the slipped stitch on the next row; like the simpler wyib, this is invisible. If knitted on the next row, the wyib slipped stitch is twice as tall as its neighboring stitches. A vertical column of such "double height" stitches is a nice accent, e. g., on a scarf or in a sweater, particularly in a contrasting color.

Mosaic knitting uses two colors (usually both held at one side), but only one yarn is handled at one time. Let the first and second yarns be called "black" and "white" for specificity, although any two colors may be used. The knitter casts on an entirely white row. The knitter then introduces the black yarn and knits two rows, across and back. If a white stitch is desired at a given position, the stitch (from the white row below) is slipped wyib; by contrast, if a black stitch is desired, the stitch is knitted using the black yarn. The second (return) row repeats the slip/knit choices of the first row, effectively giving double height. (Note that, on the return row, the stitches are slipped wyif, since the fabric is being knitted from the wrong side.) The knitter then takes up the white yarn and knits two rows, across and back. Now if a white stitch is desired at a given position, the stitch is knitted with the white yarn; by contrast, if a black stitch is desired, the stitch is slipped from the row below (if it is black). If a black stitch is needed in a white yarn row and the stitch of the previous row was white (i. e., slipped), the pattern is impossible for mosaic knitting. Therefore, any black or white vertical stripe must begin and end with the corresponding yarn, which implies that the number of knitted rows in any vertical stripe must be 2 times an odd number, i. e., 2x1=2, 2x3=6, 2x5=10, etc. However, this constraint on possible patterns can be well hidden if the pattern is large enough. Mosaic knitting can produce many beautiful patterns, particularly geometrical or Grecian designs. Historically, mosaic patterns are rather rectilinear, being composed mainly of thin horizontal and vertical stripes that meet at right angles. However, mosaic knitting has limitations relative to other techniques for producing color patterns in knitting such as Fair isle knitting. Depending on the pattern, a mosaic knit fabric may be stiff and tense, due to the many slipped stitches; such fabrics may be better for coats and jackets, which do not require as much drape. The tension in the fabric may also distort the rectilinear lines into curves. These problems may be overcome by judiciously elongating the stitches. Some color patterns may be impossible for mosaic knitting, if they require too many slipped stitches or if the colors do not line up conveniently (as described above). Blocks of solid colors can be done in mosaic knitting, but require many slipped stitches in a row; hence, blocks of solid colors are usually broken up with stippling, i. e., with regularly spaces spots of the opposing color. On the other hand, mosaic knitting is significantly lighter than Fair isle knitting, which is nearly twice as thick and bulky. Long horizontal bars of the same color are also more convenient in mosaic knitting than they are in Fair isle knitting (where such bars require that the other colors be held at the back for long runs). A simple extension of mosaic knitting is to use multiple colors, rather than just two, although the limitations on the pattern become even more severe. Another variant is to hold the yarns on opposite edges (or to knit circularly), which allows the knitter to knit only one row per color.