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Knowing Your Raw Denim: Slub and Nep

When it comes to the realm of raw denim, two of the most pertinent, yet often misunderstood, characteristics are nep and slub. Though these terms may seem like silly, redundant jargon, we can’t stress enough the importance of these denim traits. Not only do they affect the feel and texture of raw jeans, but they also impact the overall fade and evolution of any pair of denim.


Close up of a raw slub denim

Close up of a raw slub denim

We’ve previously broken down the meanings of slub and slubiness, but in essence slub refers to denim fabric made with indigo warp yarn which differs in thickness throughout. When the denim is woven and made into garments, the result will be a denim without a uniform texture which will have a much different hand than a denim woven with traditional yarns.

In some slubby denims, a technique called loom chatter is employed during the weaving process to help make the finished fabric even more textured. The layman’s explanation of loom chatter is that the shuttle looms that are used to weave the fabric are set to a low tension level while they weave.

This lower tension setting makes the looms literally shake while they weave the denim – an action which, in addition to the naturally uneven nature of the yarn used to weave the denim, makes the product even more uneven and textured.

As a picture says a thousand words, this detailed look at a pair of Naked and Famous‘ Big Slub Jeans is a classic example of some fantastic slub fades.

Fade of Naked and Famous Big Slub Jeans

Faded Naked and Famous Big Slub Jeans

Slub fading detail on Naked and Famous Big Slub Jeans

Slub fading detail on Naked and Famous Big Slub Jeans

Alternate Close up of Naked and Famous Big Slub Jeans

Alternate Close up of Naked and Famous Big Slub Jeans

Selvedge fade on Naked and Famous Big Slub jeans.

Selvedge fade on Naked and Famous Big Slub jeans

Slub will be quite textured and is able to either posses a softer or rougher feel, depending on the actual cotton used, than most raw denims. Aside from the difference in texture that slubby denim is noted for, its irregularity in yarn thickness also tends to result in more interesting fades.

Specifically, these fades tend to run more vertically along the fabric than horizontally. The reason behind the unusual fading characteristics in slub denim is very interesting as the vertical fading occurs because the indigo dyes tend to fade at different rates based on the varying thickness of the yarn used to produce the denim. This vertical fading characteristic is also known as Tate-Ochi, or “vertical falls”, in Japanese.


Nep has often been confused with slub because of the textural characteristics that they both share. However, the difference between the two often needs to be very clearly defined. Have you ever stumbled upon a pair of jeans that seemed to have little particles of white fluff protruding from the main part of the garment? It may have looked a little bit like below.

Close up on horizontal and vertical nep fades.

Close up on horizontal and vertical nep fades.

When a garment is neppy, or has nep, it usually just means that the fabric of the garment has been woven in a way that some of the cotton fibers extend and protrude from the main surface. Usually these fabrics tend to posses a “snowy” look, as if fresh fallen snow is sitting on the surface of the denim. The texture in this type of denim will be more noticeable on the surface of the fabric than the peeking glimpses of white in the composition of a slubby fabric.

Nep denim also possesses some peculiar traits throughout life of the fabric. It still fades naturally like most raw denim, but the neppy fibers will become more pronounced in the appearance of the jean; bringing about a furrier look. One of the most desirable features of a nep denim is their uncanny ability to fade horizontal, as well as vertically like the snowy nep denim below.

Snowy Nep Whiskers.

Snowy Nep Whiskers

Loom chatter also plays a role in the production of nep denim. As noted neppy denim usually has visible fibers exposed from the main surface of the fabric; fibers which are usually knots and broken fibers within the yarn that occur as it is spun and then woven. Loom chatter exacerbates the nepping process by further agitating the fibers and leaving them more exposed through the shaking and tangling of the yarn while the loom weaves.

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