A Nerd’s Guide to Right Hand and Left Hand Twill Denim

[Giles]

This is going out in the next newsletter, I therefore had to make it briefer than I would have liked.  I will add more, when I have a mo…..

A Nerd’s Guide to Right Hand and Left Hand Twill Denim
What is a plain weave?
On a loom, the warps run the length of the fabric and the weft (or “filling yarn” or just “filler”) run across the width of the fabric at 90° to the warps.  On a plain weave fabric, each weft thread crosses the warp threads by going over one and then under the next one, and so on.  The next weft thread goes under the warp thread that its neighbour went over and vice versa  A plain weave fabric, also known as a 1/1 weave, looks the same on both sides.  Examples of a plain weave are chambray and canvas (duck).

Plain Weave or 1/1 Weave

What is a twill?
Just like a plain weave, a twill fabric consists of warps and wefts.  However, in a twill weave, the weft passes under one or more warps and then over two or more warps.  The next weft will “step” or offset one warp, this creates the characteristic diagonal line (known as a “wale”) that identifies a twill fabric.  Twill weave is often designated as a fraction such as 2/1, where the weft passes over two warps and then under one (two up, one down).  Twills have a front and a back side and look different on the face and the back.  Because a twill fabric has fewer interlacings than a plain weave it allows the yarns to move more freely, which is one of the reasons that denim, which is a twill, shapes to the body well.  Finally, because a twill has an uneven surface, stains are less noticeable than on a plain weave fabric, which is good for workwear such as jeans.

A 2/1 Twill Weave

What is right hand twill?
Right hand twill or “Z” twist is the most common weave found in denim jeans.  In a right hand twill the diagonal twill line or wale goes from upper right to the lower left on the face of the fabric.  Because the direction of the weave loosens up fibres in the warp yarn you typically get a rougher, darker face to the twill and little weft of filling yarn showing through on the face of the twill.  Thus, all other things being equal, a right hand twill denim will appear darker.

What is left hand twill?
In a left hand twill or “S” twist, the wale goes from top left to bottom right on the face of the fabric.  In a left hand twill, the warp gets tightened during the weaving process, thus the result is typically a smoother face to the fabric.  Also as more of the weft (or filling yarn) is seen on the face of the fabric, the denim will often appear to be of a lighter hue than an equivalent right hand twill.

Right Hand Twill                                                                                              Left Hand Twill
(Photo, courtesy of The Tuck Shop, Singapore)

[Karol]

@Giles As relevant now as it was when You first posted it!
How about adding broken twill to this now when they are on the horizon?

[A Former User]

Nice one @Giles

[Kasi]

Nice G….

for those dummies need to understand

[bob_z]

Did IH ever did a piece in Broken Twill?

[EdH]

@bob_z They're doing all the core jeans cuts in broken twill in this season's run, in both indigo and indigo-overdyed-black, iirc.

[Giles]

@bob_z said in A Nerd’s Guide to Right Hand and Left Hand Twill Denim:

Did IH ever did a piece in Broken Twill?

https://www.ironheart.co.uk/forum/category/146/spring-summer-2023-bottoms

[alexpupin]

@Giles said in A Nerd’s Guide to Right Hand and Left Hand Twill Denim:

In a left hand twill, the warp gets tightened during the weaving process, thus the result is typically a smoother face to the fabric.

Is the described warp tightening intentional when weaving a LH twill or is the tightening only due to differences in a LH loom construction compared to a RH one?
In other words, is LH twill fabric purposely weaved with its characteristic stiffness and lighter nuance in mind? (I love my 19L :-))

[Giles]

It's purely to do with the way the warp twisted and the direction of the weave, the twist hgets tighter in LHT and looser in RHT.....

[alexpupin]

Ah, yes. I didn’t take into account the yarn twist and the effect of weaving in opposite directions.
Thanks @Giles !

[Karol]

@Giles are all IH denims 3x1 twill or you change to 2x1 with lighter oz?
It would be so cool to have the info in the https://www.ironhearteu.com/our-denims/ or in the detail of product description. And really the description would be cool for all fabrics, you have the 1x1 plain weave duck, chambray, flannel, ...
It would be super educational.

[mclaincausey]

@Karol said in A Nerd’s Guide to Right Hand and Left Hand Twill Denim:

@Giles are all IH denims 3x1 twill or you change to 2x1 with lighter oz?
It would be so cool to have the info in the https://www.ironhearteu.com/our-denims/ or in the detail of product description. And really the description would be cool for all fabrics, you have the 1x1 twill duck, chambray, flannel, ...
It would be super educational.

I think the 12 oz wabash is a 2x1

[Karol]

@mclaincausey Thanks for pointing out the error. I pasted from the earlier spot in the post and got twill out of 1x1 plain weave

[Giles]

I will add as I can.....

[Karol]

I just realized there is a thread for this - https://www.ironhearteu.com/forum/topic/2523/chambray-vs-mock-twist-vs-regular-fabric
And You @Giles made an awesome intro and introduced official notation as well!
Thanks for taking it into consideration. You guys were already pointing it out in some special situations like the IHSH-335-BLK where its diligently stated it is herringbone. It's awesome to have unified naming conventions.

[denim-dawg]

@Giles Excellent information! Cheers

[Karol]

This forum just keeps on giving in terms of introducing to the whole process.
Thanks @Giles for this awesome recommendation - WEAVING:
CONVERSION OF YARN TO FABRIC

[JeansCat]

If you open the close pictures of jeans on this site... It looks opposite. Left hand looks more fluffy, right hand is smoother.

[Karol]

I finally found a link to a free .pdf version - enjoy!

WEAVING: CONVERSION OF YARN TO FABRIC

[goosehd]

@Karol …being in IT, I am assuming you checked the site. I clicked on your link and freaked out when it was counting down to let me in…

I don’t know if this thing is common, and just want to check.