Denim Glossary – Agave Denim

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Denim Glossary

amsler slub - Attachment to open end spinning machines that allows slub and multi-twist effects at less cost than true ring spun yarn.

beam - A large spool where warp yarns are wound into a warp sheet so they can then be used for weaving or dyeing. Fabric also may be wound on beam.

bull denim - A 3x1 twill weave piece dyed fabric, made from coarse yarns. Weights can vary from 9 oz/sq yard up to the standard 14 oz/sq yard. It’s basically a denim without indigo.

calendering - A process by which the fabric is made compact, flat, and glazed. Usually the fabric surface is not flat, particularly in ordinary quality plain weave fabrics, because of the round shape of the yarns and interlacing of warp and weft at right angles to each other. In such a fabric it is seen that whilst the fabric may be quite regular, it is not flat. In calendering, the fabric is passed between the rollers of a calender machine, in which heavy rollers rotate in contact under pressure. The yarns are squashed into a flattened elliptical shape; the intersections are made to close-up between the yarns. The fabric surface becomes flat and compact. The improved planeness of surface in turn improves the glaze of the fabric. The calender machines can have several rollers, some of which can be heated and varied in speed, so that in addition to pressure a polishing action can be exerted to increase luster. (see flat finish)

carding - The industrial yarn preparation process where raw cotton is separated, opened, cleaned and made into sliver.

combing - The industrial yarn preparation process where fibers are combed to make them parallel in the sliver and short fibers and impure foreign elements are taken out.

cotton - Cotton, genus Gossypium, one of the world’s most important crops, produces white fibrous bolls that are manufactured into a highly versatile textile. The plant has white flowers, which turn purple about two days after blooming, and large, divided leaves. Length of fiber ranges from 3/8” to 2” (Egyptian, Sea Island). The longer the fiber, the higher the price and the more luxurious the fabric. Cotton withstands high temperatures, can be boiled and hot pressed. It is resistant to abrasion, has good affinity to dyes, and increases in strength 10% when wet.

crocking - The removal of dye from a fabric by rubbing. Crocking can be caused by insufficient dye penetration or fixation, the use of improper dyes or dyeing methods, or insufficient washing and treatment after the dyeing operation. Crocking can occur under dry or wet conditions. Denim is notorious for crocking, which is very hard to control due to indigo’s dye properties. (So be careful of sitting on a white sofa in new dark denim jeans!)

dips - Immersion (or dipping) of yarn or fabric into dye vats. When denim warp threads are dipped in indigo, and then emerge to oxidize, the shade darkens achieving deeper degrees of depth. Generally, indigo yarns are dipped anywhere from 8 to 16 times, but can be more or less depending on final shade and wash desired.

faux ring-spun - A variation of open-end spinning that makes the final fabric appear to be ring-spun. Although slubs appear in the fabric, it still does not have the inherent strength, softness and fastness of true ring-spun denim.

finishing - A general term which covers treatment of a fabric to give a desired surface effect such as flat, napped, mercerized, sanforized, etc. Some finishes add luster, others give a muted dull effect. Special finishes can be applied to make a fabric crease-resistant, waterproof, etc. A finish often contributes much to the “feel” or “hand” of a fabric. It may be said that “cloth is made in the finishing.”

flat finish - Special process done at mill to impart fabric with an even wash down effect and very clean surface. Originally liquid ammonia was used, but most suppliers now use mercerization plus calendering processes to achieve the flat surface. Mercerization swells up the cotton fibers and allows the calendering to press flat the surface. They consider this as an imitation process to the use of ammonia, which is toxic and not allowed in commercial use in most countries. (see mercerization and calendering)

indigo - While indigo dye was originally extracted from the Indigofera Tinctoria plant, today’s indigos are man-made. Pure indigo does not have any sulfur dye, so it is harder to de-colorize and gives a bluer more brilliant cast.

Left-hand twill - The diagonal twill line rises to the left, as opposed to a right hand twill, which rises to the right. Left hand twill is also known as an “S” weave. Is left hand twill softer? This is a matter of some disagreement with the mills who make denim, but the theory is that with a right-hand twill, the weave ‘closes” the twist of the yarn, making it tighter and more compact; but with a left hand twill, it tends to open it and make the denim feel softer. Lee has traditionally used left hand twill in its jeans.

loom - The mechanical device that waves yarn into denim fabric. There are many types of looms including handloom, treadle loom & power loom; the term loom means any weaving machine. Most denim is now made on projectile looms.

mercerization - A process of treating a cotton yarn or fabric, in which the fabric or yarn is immersed in a caustic soda solution and later neutralized in acid. The process causes a permanent swelling of the fiber, resulting in an increased luster on the surface of the fabric, an increased affinity for dyes, and increased strength. (see flat finish)

open-end yarn - A process for making coarse yarns used in denim. It is faster and cheaper than ring spinning. Fibers are fed into a high-speed rotor shaped like a cup. The end of a yarn is placed inside and drawn out as the fibers accumulate on the open end. Open-end yarns are not as strong as ring-spun yarns of the same size, because some of the fibers do not lie parallel to the axis of the yarn. You can have open-end yarn in either warp or weft (OE X RS, RS x OE) or both warp and weft (OE x OE).

Oxidation - Where oxygen and another substance chemically join. Occurs when indigo yarn comes out of the indigo bath between dips, and is critical for the dyestuff to penetrate the fiber. (see skying)

Right-hand twill - The twill line, or blue threads, rise to the right. Usually in piece dyed fabrics right hand twills use two plied yarns in the warp. In the jeans industry Levi’s has always used right hand twills for their basic 501. Levi’s research showed that the leg seams torqued (or twisted) less when they made jeans from right hand twill fabric. Right hand twill is also known as “Z” weave.

Ring dyeing - Refers to lack of full penetration of dye all the way to the core of the yarn. This effect occurs naturally in the process of indigo dyeing. When abraded, either by normal wear or through a garment finishing technique, the white core becomes exposed and affects the overall color and appearance of the garment, giving denim a unique appearance that improves with age.

Ring-spun yarn - Originally all denim used ring spun yarns, but in the Seventies, a lot of ring spinning for denim was replaced due to the lower cost of open-end spinning. Fibers are fed onto the end of the yarn while it is in the twisting zone, which consists of a ring, a ring traveler and a bobbin rotating at high speed. The yarn produced is more uneven than open-end yarn, but it is stronger and smoother to the touch because the fibers are more parallel. Because the yarns in denim are relatively coarse, open-end spinning provided a less expensive way to make yarns for denim. You can have ring spun yarn in either warp or weft (RS x OE, OE x RS) or both warp and weft (RS x RS).

Rope dyeing - Considered as the best possible method to dye indigo yarns. The yarns are twisted into rope before being dipped into the indigo dye. 300- 400 ends (or threads) are gathered to form a rope, and then 12-36 ropes are dipped into a series of dye boxes along an indigo dye range.

Selvedge - Also spelled selvage. The small woven edge that is parallel to the warp, and that prevents the cloth from raveling. All denim has selvedge- otherwise it would unravel, but normally with wide looms it is hard to detect and blends into the fabric. Old 28/29 inch shuttle looms produced denim where selvages were closed with a colored yarn. The color was used so mills could easily identify each customers fabric - vintage Levi’s jeans had a single red stripe along both selvages, Lee’s had a blue/green along one, Wrangler’s was yellow. Now authentic selvage is very expensive, as only a few old looms are still working and high-end Japanese denim mills own most of these. Why is selvedge better? First it just looks cool, especially if you roll your jeans up. Second it is rare, so not every jean has it. Third, it is considered more “authentic”, thus stronger (ring/ring) and has more character than regular non-selvedge denim. Though with the technology currently available to mills, this is not necessarily true. Mills now have ability to create very authentic ring spun denim on wider looms (without colored selvedge) that are as strong and have as much character as vintage selvedge.

Shade - While all denim is blue, every mill offers its own specific cast or hue, which is generally referred to as shade. Shade can be affected by where indigo dye was purchased, size of dye vats, whether sulfur was mixed with indigo, etc. Because of this, every denim quality will wash down differently depending on the mills dye recipe. In order to give customers a vast range of wash options, it is important to buy cloth in a variety of shades (pure indigo, blue/black, sulfur top, sulfur bottom, etc.). If you start with only one denim shade, the range of possible washing is limited.

Shade batching - The process of selecting batches of fabrics into homogeneous shade lots to obtain consistent color continuity in garment making.

Shade blanket - Where fabric is cut from each roll of fabric, sewn together, with roll numbers on the back of each pad to allow manufacturers to wash and identify all shade colors of each roll. This is an important tool in cutting apparel made from denim to ensure you cut garments from the same shade group.

Shuttle - The weft insertion device that propels the filling yarn across (over and under) the warp yarns. Shuttles used to be (shuttle looms) wooden with a metal tip.

Singeing - A phase of finishing when the fabric surface hair is burnt (or singed) using a controlled flame, to give a clean appearance to the fabrics.

Sizing - Mills coat yarn with polyvinyl alcohol and starch for strength, and paraffin to make it easier to weave into cloth and handle in sewing.

skying - Process in which the indigo dye is oxidized, or exposed to the air, a step that is necessary to develop and fix the color. (see oxidation)

slasher dyeing - Slasher Dyeing dyes the yarns in warp beam form. It is a continuous process which combines dyeing and sizing in a single operation. Dyeing is done by continuously passing warp yarns in beam form through several (at least 5) troughs of indigo dye liquor. The dyed yarns are then sized and wound onto a warp beam to be ready for use in the weaving process. Slasher dyeing is usually of inferior quality as compared to rope dyeing in shade evenness or side-to-side shade variations. With the slasher dyeing, the penetration of dyestuff is poorer, and it easily reveals an uneven pick-up along its width with the distortion of the pad-roll. Also, in rope dyeing, the yarns of the ropes have to be rebeamed, and be sized to the final warp beam. In this mixing process, small dyeing faults and minor variations in dyeing will be obscured.

sliver - Continuous strands of fiber untwisted that come from carding.

slub yarn - A yarn that is spun purposely to look irregular in shape (length and diameter). Usually slub yarns are very regular in repeat and size. Denim made with slub yarns have the benefit of showing white streaks after denim is stonewashed, so it provides a garment with more character and interest.

spinning - Spinning is the process where fibers are twisted to produce a yarn or thread suitable for weaving into cloth, winding into rope or cable, or used in sewing.

staple - Short lengths of fibers, normally measured in inches or fraction of inches, like those naturally found in cotton and wool.

sulfur bottom - Process in which warp yarns are pretreated with sulphur dye prior to being dipped into indigo. This promotes a quicker wash down (the sulphur protects the yarn’s core from the indigo), and can change the cast or hue of the denim to yellow or gray for a vintage look. Sulphur bottoms can be regular, heavy or extra heavy, depending on the desired effect.

sulfur top - Yarns are sulphur dyed after they have been indigo-dyed. This adds depth to color and is sometimes used to create novelty looks.

warp - The lengthwise, vertical yarns carried over and under the weft. Warp yarns generally have more twist than weft yarns because they are subjected to more strain in the weaving process and therefore require more strength. A single warp yarn is known as an end.

weft (also called filling) - The lengthwise, selvage-to-selvage horizontal, yarns carried over and under the warp. Filling yarns generally have less twist than warp yarns because they are subjected to less strain in the weaving process and therefore require less strength. A single filling yarn is known as pick.

weaves - Warp and weft yarns are combined in different ways to produce different weave designs. These designs affect the appearance, feel, strength and durability of the denim. The simple warp face designs used in denim are designated by the number of weft yarns that the warp ends pass over, followed by the number of weft yarns they pass under. The most common weaves in denim are three over one (3/1 or 3x1), two over one (2/1 or 2x1), and three over one broken twill. The 3/1 and 2/1 come in either left- or right-hand direction. The most common design in denim is the 3/1 right-hand twill.

Denim Washing Terms

abrasion - Laundries try to make garments look worn or faded by scraping or rubbing the surface of the fabric causing abrasion. Pumice stones, sandpaper, grinders, etc provide mechanical abrasion. Enzymes, bleach, permanganate and reducers are used to get chemical abrasion. Abrasion gives nice color loss at seams but should not cause actual tears to fabric.

acid wash - The iconic wash of the 80’s. Acid wash was patented by the Italian Candida Laundry in 1986. The process is achieved by soaking pumice stones in chlorine bleach and then dry tumbling them with jeans before washing. This creates very irregular, hi-contrast splotches over the entire surface of the garment.

bleach - Laundries use this chemical to make denim jeans fade. Liquid bleach is usually an aqueous solution of sodium hypochlorite, and dry powdered bleaches contain chloride of lime (calcium hypochlorite). Chlorine bleach attacks all colors in fabric both indigo and sulfur so it needs to be used sparingly as it flattens the look of the fabric. Good laundries will use longer wash cycles and less bleach to achieve maximum hi/low effects.

balloon form (or manikin) - Mechanical form made of heavy-duty inflated rubber that mimics shape of human legs. Garments are put on the form when machine sanded or PP sprayed to control garment stability and give more natural blast patterns. Balloon forms can come in adult or children’s sizes also they can come in jacket forms.

blast pattern - The actual position on the garment where you want sandblast, hand sanding, grinding, etc. applied. You should always to try to give laundries a sketch that show desired blast pattern to avoid confusion.

contrast - Very useful term when describing the desired blast effect. In describing blasts, you should avoid terms like “lighter” and “heavier” as they can be misleading. (For instance you may say you want a lighter blast, meaning you want it to be lighter in color, but laundry may mistake this for lighter intensity and will give you a darker, less apparent blast.

Hi-contrast means you want the blast area to be very apparent, and stand out against the ground color (base wash) dramatically. Using PP (potassium permanganate) will give you hi-contrast effect.

Medium-contrast is most common - you get good contrast between blasted area and ground, not too dramatic, but not soft enough that it is invisible. Usually achieved by sandblasting or machine brushing.

Low-contrast means you want blast to be subtle, and very soft, with minimal color loss. Generally hand sanding gives you the softest blast effects, but hand sanding will disappear in lighter washes.

chevrons- The lines that form on inner thighs of jeans (as opposed to lap which are called whiskers) from continued wear. The process is the same as used to apply whiskers - by hand using either a sanding tool alone or with PP depending on contrast desired.

de-sizing - The wet processing operation of removing the warp size chemicals and finishing starch from the fabric. Laundries generally use amylase, a starch-busting enzyme found in saliva, or alkaline chemicals like soda ash to remove the sizing. If sizing isn’t removed prior to washing, streaks and cracks can result. For darker washes a fixing agent is added during de-sizing to hold dye in the fabric and decrease crocking. (also see sizing in fabric terms)

enzymes - Cellulose enzymes (a protein-like substance) are used to actually eat away at the cotton fibers and create a stonewashed look. The combination of the surface-to-surface abrasion of the garments and the garment to machine abrasion creates an overall stonewashed appearance.

feathering - There term used when you want to explain to the laundry that you want a nicely blended blast pattern. A typical blast should look strongest at the center, but gradually decrease in intensity at edges so that it blends into the ground color, with no harsh lines. To get feathering the laundry may need to hand sand around sandblasted area to soften the lines. (see sandblasting and contrast).

flat - Calling a wash flat can be either good or bad depending on what look you were trying to achieve. When used as a negative, it means you do not see enough contrast between blue (ground) and white (fill yarn or fabric slub). This can occur from washing with only enzymes without stones, or from poor cleaning up of the garment in the wash. (see re-dep) When used as a positive, it means you want the denim to wash down very cleanly and evenly, and only want hi/lows on seams not on surface (see flat finish in fabric terms).

grinding and nicks - Using a mechanical device to chip away at the basic to break the yarns and get small tears. The difference between grinding and nicks is amount of surface covered. Grinding is generally any tearing of 1/4 inch or more in length while a nick is any tear under 1/4 inch in length. Most commonly used at bottom hem and pocket edges, but you can specify grinding or nicks on any part of the garment.

hand sanding - Using sandpaper to scrape away the top layer of indigo from the fabric. Hand sanding denim gives it the most natural, worn effect as the laundry operator can adjust the pressure used, and blend the blast pattern with the ground.

laundry - A manufacturing company that takes unwashed jeans, and processes them. This processing includes washing, stone washing, sandblasting, and garment dyeing. Laundries today are critical in making jeans look commercial and wash development has become equally important to fabric development in the denim industry. The best laundries and wash developments come from Italy, Japan and the United States.

machine brush - A high powered electrical steel bristle brush that when run over denim quickly chips the indigo away. Sandblasting and machine brushing give very similar effect.

pocket outline - A surface technique where the jean is placed on the balloon form, and the laundry technician headily hand sands over the pockets. The pressure of the sanding accentuates the inside seam of the pocket bag and you see it  on the jeans surface. This gives a more natural effect than drawing the shape onto the garment. (also see stencil)

potassium permanganate (PP) - A dark purple crystalline compound KMnO4, used as an oxidizing agent and disinfectant and in deodorizers and dyes. PP can give very dramatic hi-contrast blast patterns. PP when applied is a purplish color but garments are then neutralized which causes the areas where PP is applied to turn white. PP can be applied by spray to get overall blast pattern, or can be applied by brush or sponge to just affect specific areas.

pumice stones - Pumice stones are used in wash to chip away layers of indigo from the denim. Pumice is volcanic and is used because of its strength and light weight. The preferred pumice to use is Turkish White Pumice Stone as it has the best porosity and cleanliness. Turkish white pumice should be specified when doing light washes or stone washing twills as it leaves less residue on fabric.

re-dep (short for re-deposition, also referred to as back-staining) - when indigo comes off in wash, but due to poor cleaning the indigo falls back onto the fabric and you get a very flat wash (no hi/lows). The easiest way to tell if the flat look of wash is caused by re-dep is to check the pocket bags, if they are tinted blue then the laundry is not cleaning up after wash, and probably needs to use an anti-back staining agent.

reducers - Chemicals that remove color from fabric. Special reducers (like Laccase) can attack specific dyestuffs like indigo but leave sulfur dyes in fabric to achieve different casts.

resin - A synthetic polymer that is used to set wrinkles into a jean. Jeans are treated with resin, and then baked in an oven so chemicals can merge with fibers to set color, stiffness, and make creases permanent. Resin will set color into the jean, so will reduce crocking where applied. But be careful, as resin will effect the denims tear/tensile strength and make the fabric weaker and more brittle. Also resin contains formaldehyde so may be problematic for production of children’s jeans.

rigid denim - Unwashed denim. Some mills use this term to refer to non-stretchy denim, though to avoid confusion with garment makers it should be reserved as a wash term and use the terms stretch and non-stretchy for fabric type.

rinse - The mildest, least severe garment wet processing finish during which the sizing, natural waxes, pectins and starches are removed from fabric. Only a minimal color loss is achieved.

sand blasting - A laundry process where jeans before washing are literally shot with a high-powered spray of sand that chips off the outer layer of indigo. While actual sand was originally used now most laundries use very small aluminum oxide pellets. If blast is applied improperly you can get a very harsh, unnatural contrast between the ground and blasted area in the garment.

softeners - Softeners can be classified into the four major groups:

1. Anionic softeners have poorer affinity for cotton. Most of them shows good stability towards heat and have better resistance to yellowing. However, softness of anionic softeners is inferior as compared to cationic, even with high concentration. Also, they are easily removed and have low durability to launderings.

2. Cationic softeners provide very soft hands at even low levels. They have efficient exhaustion from high or low liquor ratio baths. However, Cationic softeners have a tendency to yellow the garments.

3. Nonionic softeners have little effects on fabric shades and are quite non-yellowing. However, the hand is not as good as the other softeners. It is not as durable as cationic, but more durable than anionic softeners.

4. Silicones impart a silky, slick, greasy, full hand on the surface of the materials. It improves the abrasion resistance but reduces absorbency. Normally, silicones are used with cationic softeners to provide ultra-soft and smooth hand feel.

stonewash - The most common way to wash denim. Pumice stones, in combination with enzymes (and sometimes bleach), are added in the wash to get abrasion on denim. Water temperature, stone size and length of load time all affect final wash appearance.

tacking - A technique that folds or scrunches several layers of denim, and attaches it together by swift-tach or sewing thread before wash. After wash it is released to reveal a pattern of light areas where stones hit the folds, against dark areas where what did not penetrate.

tinting (also called over-dyeing) - Laundries often tint denim to try to make it look more vintage, or to achieve a different cast. The telltale signs of a pair of jeans that have been tinted are that the pocket lining and labels are dyed as well as the jeans.

whiskers - The lines that form on the lap and legs of jeans from continued wear. Most whiskers are applied at the laundry by hand using either a sanding tool or PP depending on contrast desired.