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March 13 - Knowing Your Raw Denim: Slub and Nep

March 13 - Knowing Your Raw Denim: Slub and Nep

Our comprehensive guide to slub and nep, two often mentioned but lesser known facets of denim fabric.

David Shuck
March 13, 2024

Knowing Your Raw Denim: Slub and Nep

Our comprehensive guide to slub and nep, two often mentioned but lesser known facets of denim fabric.

Dennis Deprimo and James Smith

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.

Slub

Close-up of some slubby denim by Samurai. Image via Redcast Heritage

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. This results in denim without an uneven, sometimes rough texture which will have a much different hand than denim woven with uniform yarns.

In some slubby denim, 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.

Slubby denim can either possess a softer or rougher feel than most raw denim, depending on the cotton used. 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.

Faded slubby selvedge denim from Hanzo ‘The Raid’ Jeans. Notice the unique waterfall texture caused by the slubby weave of the denim, which has emerged as the denim has faded.

Nep

An extreme example of Nep via Naked & Famous.

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.

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 possess a “snowy” look, as if freshly 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.

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 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.