For all of you non-fabric geeks, selvages are the edges of the handwoven fabric that do not require any hemming and will not fray after the fabric is taken off the loom.
The straightness of the selvages is often viewed as the ultimate proof of a weaver’s skill. During weaving I fret and worry about my selvages, and I know other weavers do that too. Well, are the selvages really a testimony to a weaver’s skills? Let’s do a deep dive on this topic.
In my experience, the selvages are a product of four factors: weaving structure (pattern), weft yarn, weaver’s equipment and weaver’s skills.
Let’s look at each of them in more details.
First, the weaving pattern. Plain weave will give the most straight selvages, as there are no floats at the edges. As soon as we move into the land of twills, we get floats. A float is a thread that goes over several threads (or under) in weaving. The floats can be in warp and in weft. And floats are not bad, mind you – they create all these intricate patterns. 
In that picture you can see the long floats of the pink weft yarn, creating the beautiful pattern called “Gertrude’s fancy”. The weft floats are created when the same shaft is lifted 2 or more times as the shuttle is thrown. While that creates pattern on the face of the fabric, it also creates an uneven look in the selvages. Those scallop-like threads at the end of the fabric in the photo below are exactly these floats. So, this pattern will not give straight selvages regardless of the skill level of the weaver. And there are many patterns like that in the handwoven world.
Let’s move to the next one: the weft yarn. The thickness, the elasticity, and the evenness of the thread all play into the how the selvages will look. As you can guess, inelastic yarn will get less even selvages as it will bend less uniformly at each turn at the selvage. Thick yarn loops at the selvages are more visible, as they are bigger, than a finer weft, so finer weft will have more even selvages appearance.
The third factor is equipment. An electric bobbin winder gives more uniform tension than hand-operated winder. End-feed shuttle is better for selvages than the regular shuttle. Having more than 4 shafts on the loom may give an opportunity to add a column of the plain weave at each end of the fabric in addition to a pattern with floats – we do remember that the plain weave will give the straightest selvages out of all weaving patterns, right?
Now we get to the point of a weaver’s skills, finally. Yes, it is important how a weaver throws a shuttle: the angle of the weft thread, the evenness of the throwing motion, the consistent rhythm of weaving. But all the skills a weaver has is only a portion in the recipe for even selvages.
And there is so much more to the fabric than selvages. The consistency of the weft density, the use of knots or overlaps to change weft or fix a broken warp thread, the error-free threading so there are no errors in the patter… the list goes on and on and on.
My final point is this: if the selvages are important to you, tell your weaver, and she will help you pick the right weft yarn and weaving pattern to avoid the factors that go against the selvage evenness. Also, the uneven selvages are not a safety threat for baby wraps: I hope that I showed enough examples above for floats and type of yarn to disprove this perception.
And, as usual, if you have questions or comments, let me know.
THE SILKY WEAVE 