Selvedge vs. Normal Denim
There are two different ways to weave denim: with or without a shuttle. Weaving with a shuttle is the traditional way.
The shuttle is substantially necessary; it guides the weft thread through the warp shed. As the weft is constantly moved back and forth, the edges of the fabric are finished by themselves, which is why it is also called "selvedge".
Weft-less weaving is usually done with a projectile loom. Instead of a shuttle, the weft thread is carried across the shed by a small metal device that looks like a projectile (hence the name).
What makes Selvedge Denim so special?
Selvedge is the name for the higher quality, more complex to fabricate type of denim that is usually being sold and worn unwashed. You can recognize it by the cuffs of the jeans. If they have a clean finish with edges that are usually white/red/white, it is Selvedge denim.
In fact, Selvedge should be spelled "self-edge". The term refers to the self-edging edges of selvedge woven fabrics. The issue here is weaving, which we need to get an understanding to know what selvedge is.
Why is selvedge denim more expensive?
Shuttle-less looms generally weave at an average of at least four times as fast as shuttle looms. And because the weaving frame can be made wider, the production output is up to ten times higher. In other words, you can weave 10 times as much denim per hour when it is not selvedges, and this of course has an impact on the price.
Another important cost factor is the fact that all looms are old and need a lot of care and maintenance to keep them looming.
Is denim with selvedges better?
This is not an easy question to answer. If by "better" you simply have in mind "longer lasting", the answer is: no.
The fact that denim is made of selvages does not mean that it is longer lasting! But because most selvedge denims are not washed in a factory, they do last a slightly longer time.
What's better about selvedge denim is the way it fades, I think most of us can agree on that. Obviously, these are opinions and not facts.
A fact is that there is less tension on the yarn due to the slower speed of the looms. And it is a fact that looms with shuttles allow more spots in the yarn, which give the denim its character and a quality.
Selvedge denim is difficult to make and requires a traditional loom and more time and effort than regular denim. But in return, you are rewarded with fabrics of the highest quality and unique character that you cannot get with a modern weaving method.