If your eyes glaze over as soon as “technical” things come up, you’re not alone. But you can’t be a successful seamstress without understanding your materials.
Grain is just a fussy word for direction. Fabric is woven on a loom, where the crosswise – weft – yarns are woven over and under the lengthwise – warp – yarns (yes, they look like threads, but technically even the tiniest ones are called yarns). The lengthwise yarns are held at extremely high tension during weaving, while the crosswise yarns are looser. This affects how fabric behaves when you sew, and it means that grain line arrows on patterns aren’t just suggestions. Designers use grain strategically, as part of the shaping process. If you ignore these lines it will show in the finished product, guaranteed.
Stop reading for a minute and grab a small piece of fabric. If you start “pulling” it with your fingers in various ways, you’ll notice immediately that some directions have more “stretch” than others. The least amount of give is along the lengthwise grain, because these are the yarns that were at high tension on the loom. The lengthwise grain runs parallel to the selvage, and designers use this cutting direction for pieces that need to remain stable under strain. Waistbands, for example, are almost always cut to have the lengthwise grain going around the body, to prevent them from losing their shape with wearing.
The direction with most give is at a diagonal. High fashion skirts and dresses are sometimes shaped exclusively by placing pieces on varying degrees of bias rather than with darts or seams. And you’ve probably taken advantage of stretchy bias cutting to create flexible bias binding. But did you know it’s also used to make collars lie perfectly? The point where a collar must roll the most – over the shoulder area – is always cut on some degree of bias.
“If you’re not careful, grain can work against you. . .”
Waistbands, bias binding, and collars are a few of the many ways to put grain to work for you. But if you’re not careful, the grain of your fabric will work against you. For example, if you cut a skirt with a gathered waistline off grain, it won’t matter how much you fuss when you pull up the gathers because you’ll be fighting against the natural tension of the fabric’s yarns. Nothing can ever hang neat and straight if it’s been cut crookedly. So never forget that beautiful gathering begins with beautiful cutting.
There are many more examples of how grain affects the shape of a finished item. But the moral of this story is simple. Cutting off grain, even a little bit, means you’re cutting slightly on the bias. And things cut on the bias stretch whether you want them to or not. So unless you want your fabric to fight you all the way, make sure those little arrows are placed exactly on the lengthwise grain before you cut. It makes all the difference in the world.