Saturday, May 7, 2016

Knitting
Art Resource

Marie-Therese Wisniowski

Preamble
This is the fifty-second post in the "Art Resource" series, specifically aimed to construct an appropriate knowledge base in order to develop an artistic voice in ArtCloth.

Other posts in this series are:
Glossary of Terms
Units Used in Dyeing and Printing of Fabrics
Occupational, Health & Safety
A Brief History of Color
The Nature of Color
Psychology of Color
Color Schemes
The Naming of Colors
The Munsell Color Classification System
Methuen Color Index and Classification System
The CIE System
Pantone - A Modern Color Classification System
Optical Properties of Fiber Materials
General Properties of Fiber Polymers and Fibers - Part I
General Properties of Fiber Polymers and Fibers - Part II
General Properties of Fiber Polymers and Fibers - Part III
General Properties of Fiber Polymers and Fibers - Part IV
General Properties of Fiber Polymers and Fibers - Part V
Protein Fibers - Wool
Protein Fibers - Speciality Hair Fibers
Protein Fibers - Silk
Protein Fibers - Wool versus Silk
Timelines of Fabrics, Dyes and Other Stuff
Cellulosic Fibers (Natural) - Cotton
Cellulosic Fibers (Natural) - Linen
Other Natural Cellulosic Fibers
General Overview of Man-Made Fibers
Man-Made Cellulosic Fibers - Viscose
Man-Made Cellulosic Fibers - Esters
Man-Made Synthetic Fibers - Nylon
Man-Made Synthetic Fibers - Polyester
Man-Made Synthetic Fibers - Acrylic and Modacrylic
Man-Made Synthetic Fibers - Olefins
Man-Made Synthetic Fibers - Elastomers
Man-Made Synthetic Fibers - Mineral Fibers
Man Made Fibers - Other Textile Fibers
Fiber Blends
From Fiber to Yarn: Overview - Part I
From Fiber to Yarn: Overview - Part II
Melt-Spun Fibers
Characteristics of Filament Yarn
Yarn Classification
Direct Spun Yarns
Textured Filament Yarns
Fabric Construction - Felt
Fabric Construction - Nonwoven fabrics
A Fashion Data Base
Fabric Construction - Leather
Fabric Construction - Films
Glossary of Colors, Dyes, Inks, Pigments and Resins
Fabric Construction – Foams and Poromeric Material
Hosiery
Glossary of Fabrics, Fibers, Finishes, Garments and Yarns
Weaving and the Loom
Similarities and Differences in Woven Fabrics
The Three Basic Weaves - Plain Weave (Part I)
The Three Basic Weaves - Plain Weave (Part II)
The Three Basic Weaves - Twill Weave
The Three Basic Weaves - Satin Weave
Figured Weaves - Leno Weave
Figured Weaves – Piqué Weave
Figured Fabrics
Glossary of Art, Artists, Art Motifs and Art Movements
Crêpe Fabrics
Crêpe Effect Fabrics

The Glossary of Terms, Timelines of Fabrics, Dyes and Other Stuff, A Fashion Data Base, Glossary of Colors, Dyes, Inks, Pigments and Resins, Glossary of Fabrics, Fibers, Finishes, Garments and Yarns and Glossary of Art, Artists, Art Motifs and Art Movements have been updated in order to better inform your art practice.

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The Art Resource series will be the first post in each calendar month. Remember - these Art Resource posts span information that will be useful for a home hobbyist to that required by a final year University Fine-Art student and so undoubtedly, some parts of any Art Resource post may appear far too technical for your needs (skip over those mind boggling parts) and in other parts, it may be too simplistic with respect to your level of knowledge (ditto the skip). The trade-off between these two extremes will mean that Art Resource posts will hopefully be useful in parts to most, but unfortunately may not be satisfying to all!


Introduction
Knitting is a process by which needles are used to form one or more yarns into a series of interlocking loops. A knitting machine can make fabrics 5 to 10 times faster than a loom. It is possible to fashion garments by knitting so that they need not be cut and may be sewn as woven fabrics. Knitted fabrics are in unprecedented demand today. The increased opportunity to travel, interests in leisure time activities such as sports, informal relaxed living styles and emphasis of easy-care fabrics have been responsible for the expansion of knits in the fields of outerwear apparel, home furnishings and automotive textiles etc. New technological developments in knitting machinery, new ideas in knitting construction and new finishes have contributed to the use of knots in high fashion garments and in the use of wearable art.

Libby Peacock and her eldest daughter, Fenella, design hand knitted collections of evening-wear.

Laminating knits to polyurethane foams have made it possible to use thin and in some cases uneven knits such as jerseys for outerwear. In bonded fabrics acetate filament tricot is widely used as a backing fabric.

Recycled sweaters cover the polyurethane foam and wood.

Knits are desirable because they do not wrinkle easily, shape to the body without binding, are elastic, porous, yet light and warm.

Brett Whiteley’s Jacaranda Tree – interpreted in knit wear by Ruth Fitzpatrick [2].

Some of the advantages may also promote other disadvantages. For example, the unstable shape of the knit stitch results in the loss of shape and size in many cotton, rayon and wool garments. They are warm in still air but must be covered by a wind-repellent layer to keep the body warm on a windy day. On a warm humid day, knits may be too warm because they tend to fit snugly and keep the air close to the body.

Vida Lahey’s Lunchtime – interpreted in knit wear by Libby Jones [2].

Knits may be made of any fiber. Spun yarn used in knitting is of rather low twist and must be made very uniform or else thick-and-thin places will occur in the fabric. Synthetic filaments are uniform and easy to knit.

Ikat print filament knit.


Methods of Knitting
The two methods of knitting are warp knitting and filling knitting. These terms are borrowed from weaving techniques and refer to the way loops are formed.

Comparison of warp and filling (weft) knitting.

Warp Knits
Warp knits are machine knits from one or more sets of yarn placed side-by-side, the same position as warp yarns for weaving. Warp knitting started around 1775 with the invention of the tricot machine (or warp loom) by Crane of England. The machine knitted fabrics 16 inches wide and was primarily used for silk stocking cloths. The development of this machine was unique in that there is no evidence that warp knitting was practiced as a hand technique. In 1880 Kayser established a warp knitting mill in the USA.

One of Kayser's beautiful design for silk gloves now housed at The Metropolitan Museum of Art.

Warp knitting provides the fastest means of cloth fabrication. The loops are all made simultaneously by interloping individual warp yarn into loops of adjacent warp yarns. The loops form vertical wales on the right side and horizontal wales or courses on the wrong side.

Two-bar tricot fabric. Top: face side. Bottom: reverse side.

A modern warp knitting machine. It can knit fabric up to 168 inches wide and can produce 1,000 courses and 4,700,000 stitches per minute.

Modern warp knitting machines

Fabrics are usually knitted flat and are made on several different types of machines. Those most common are the tricot machines employing a single needle bar with two guide bars for plain fabrics (see above) or two to four guide bars for pattern fabrics, and Raschel machines having one or two needle bars and up to 30 guide bars. The guide bars lay the threads around the needles.

Diagram showing motion of the guide bars in knitting.

Tricot
Tricot (pronounced tree’-ko) comes from the French word tricoter meaning “to knit” and is the name given to warp knit fabrics, which are widely used in underwear, dress and blouse fabrics and backing fabrics. They are either run- or snag-resistant or runproof.

Tricot jersey fabrics are knitted 160 inches wide and cut into 40 inch widths for sale as yard goods or for use in ready-to-wear garments. Most tricot fabrics are made from filament yarns. Nylon jersey is heat-set to stabilize the fabric. If it is off grain, it cannot be straightened because the yarns have been set and will not assume another position when they are wet. Acetate tricot is used for backing in most bonded fabrics and has wide use in textured knit for dresses. Arne tricot is less expensive than nylon and is employed in the same end uses.

108 inch 40 denier tricot turquoise

New developments in tricot have been made by stitch construction, by yarn construction, by finishing or by combining these. Effects achieved by stitch construction are:
(i) over-all clipped dots made by a third set of yarns put in as a lappet design as is done in woven fabric
(ii) a tucked fabric
(iii) a ruffled tuck
(iv) simulated pleats in which some of the fabric is sheer and some heavier.

Effects achieved by yarn construction have been mainly in improving the feel or hand of the tricot. Using trilobal nylon (Antron) has given warmer, more silk-like hand. Textured nylon and acetate (Taslan, Ban-Lon) yarns are used to give better hand. Crepset nylon makes sheer tricot. This fabric looks like chiffon or georgette and has the appearance of true crepé without the high potential shrinkage due to high-twist crepé yarns. Novelty yarns can be used for special effects, but at present are rarely commercially employed.

Nylon taslan dobby.

Effects achieved by the finish include cross-dyeing for striped designs or leather effects, embossing for surface design, or opaqueness and burnt-out designs. The most important embossed finish is Shreinering, a process in which round yarns are flattened to give more cover – to make fabrics look and feel flatter. Other embossed finishes give a leather-like look to fabrics. Burnt out designs are made by knitting in an extra yarn of unlike fiber content and printing an acid or caustic on the fabric to remove sections of the extra yarn.

One fabric finish is Shreinering. The natural luster of many cloths such as cotton-back satin, satin, muslin, linen and lining is enhanced by a method of milling or pounding called shreinering. The material is subjected to the physical action of a roller, usually made of steel, with a great many fine lines per inch engraved in it. The roller flattens the threads in the cloth and imprints onto the surface a series of ridges so fine that it is necessary to use a microscope to see the fineness of the work. These very fine lines reflect the rays of light and bring out the appearance by which the cloth is characteristically known. Some of the finishes allied with shreinering are frost-shreinerization, imitation schreinerization, imitation mercerization and bloom finish.

Raschel knitting machines combine high productivity with extensive pattern designs. They knit anything from very fragile hairnets, tulles and veilings to coarse rugs and fur cloths. Elastic fabrics for foundation garments are made on Raschel machines.

Drawing of a power net, knitted on a Raschel machine.

Filling Knits
Filling knits are made with one or more yarns carried back and forth to make a flat fabric or are knitted completely around to make a circular fabric. Filling knits are made both by hand and by machine. An experienced hand knitter might produce 60 stitches per minute while a machine can produce at least 3 million stitches in the same time.

A circular knitting machine for filling knits.

Filling knit fabrics are usually a plain knit or rib knit. A third stitch or purl stitch is used to make imitations of hand-knit garments for children and in combination with plain or rib knit in patterned fabrics.

This fabric contains the vertical wales, which are characteristic of a filling knit.

Plain knit is one in which the loops are drawn to one side of the fabric. These knits have a definite right and wrong side with wales on the face side and courses on the reverse side.

Plain jersey stitch. Right: face side. Left: reverse side.

The face of the fabric has more sheen than the back. Plain knit is also called jersey stitch, named for the turtle neck sweaters originally worn by sailors from the Isle of Jersey. The stitch is used in knitting sweaters, yard goods in dress and suiting weights, sport shirts and hosiery.

Jersey purple. A basic stitch used in weft knitting, in which each loop formed in the knit is identical. The jersey stitch is also called the plain, felt, or stockinet stitch. Jersey fabric is created through the consistent inter-looping of yarns in the jersey stitch to produce a fabric with a smooth, flat face, and a more textured, but uniform back. Jersey fabrics may be produced on either circular or flat weft knitting machines.

Rib knit is made by drawing every other stitch to the face of the fabric. These fabrics look the same on the right and wrong side. Rib knits have more elasticity crosswise than plain knits and are therefore used as wrist and neckbands on sweaters. Rib stitch is also used in making bulky knits. It is seldom used in yard goods for outerwear garments but is used in underwear fabrics. Rib stitch fabrics do not curl at the edges as do plain knits.

Plain 1 and 1 rib stitch.

Purl stitch knits look the same on the face and reverse side and look like the reverse side of jersey. This stitch is used to make sweaters, especially for infants and children and booties. The fashion for bulky knits has increased the use of this stitch. Purl knits have excellent stretch both crosswise and lengthwise.

Purl stitch.

Tuck stitches are made by collecting more than one loop on a needle and then drawing a single loop through them. Lacy or meshed fabrics are formed in this manner.

Tuck stitch. A knitted stitch, which produces a tuck effect by having certain needles carrying more than one loop at a time. The resulting stitch produces an elongated wale (lengthwise ridge) on the front of the fabric, while on the back of the fabric the tuck stitch appears as an inverted plain stitch. The stitch can be elongated for two or more courses (rows of loops/stitches), depending on how often the stitch was tucked.

Jersey, which is made in tabular form, is seldom pressed at the factory with wales parallel to the creases of the fabric, and the courses or crosswise ridges straight with the cut edge. Before cutting a garment from jersey, put a basting line or a line of pins along a wale to mark the lengthwise grain, refold the cloth, and then straighten by steam pressing or wetting the fabric. A very small needle should be used in stitching.

Lacoste men's cotton jersey V-neck sweater.

Double knits are made with two sets of needles, creating firm fabrics that have more body and durability than single knits. They have the good characteristics of regular knits, and in addition are less apt to “sit out”, require no skirt lining and can be hung on hangers. They are easier to handle in cutting and sewing since they do not curl on the edges.

Double knit scarf.

The most commonly used stitch is the double piqué stitch, which gives a subtle diamond-like effect surface. The double piqué stitch is made on specially designed circular equipment and is most attractive in finer gauges. Other double knit constructions are ribs, single piqué and bourrelet. Bourrelet is a ripple stitch or corded fabric made by raising loops across the surface.

Bourrelet headdress, which has been reproduced from a stunning 15th Century effigy - Lady Margaret Herbert of Coldbrook (wife to Sir Richard Herbert of Coldbrook).


References:
[1] N. Hollen and J. Saddler, Textiles, 3rd Edition, MacMillan Company, London (1968).

[2] J. Rogers, The Art of Knitting, Collins, Angus and Robertson, North Ryde (1991).

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