Thursday Tip with Hali - What is a grainline?
Thursday Tip // What is a grainline?
If you are just getting into sewing you may have seen the term “grainline” floating around and showing up on almost every pattern piece you work with. It is typically marked by a long straight line with an arrow on each end. The grainline indicates how you should position the pattern piece on the fabric. For pattern pieces cut on the fold the grainline is the “cut on fold” line with arrows indicating which edge is placed on the fold.
If you are new to this term and aren’t sure why grainlines are important then read on, my friend.
ID: A light blue grey piece of fabric with a multicoloured selvedge is laying on a white background. A graphic showing the direction of different grainlines is overlayed on top of the fabric swatch.
When fabric is woven on a loom there are threads running in two general directions, side to side and up and down, if you will. The “grain” or grainline refers to the direction the threads are running. Technically grainline is talked about in woven fabric terms but it is a word readily used for knit fabrics as well.
There are three different types of grainlines, however, we most commonly refer to grainline as being the lengthwise grain running the length of the fabric parallel to the selvedge.
Lengthwise yarns (or “warp” yarns) run parallel to the selvedge edge (factory finished edge, usually identified by a slightly different weave or thread color that keeps the edges from unraveling). These yarns are stronger and more stable because they are more tightly twisted than crosswise yarns.
Crosswise yarns (“weft” yarns) are perpendicular to the selvedge. These yarns are woven under and over the lengthwise yarns to create the unique weave of the fabric. Crosswise yarns tend to be less stable than lengthwise yarns.
The bias is any diagonal direction on the fabric with the true bias being the 45 degree angle between the lengthwise and crosswise grains. Fabrics will typically stretch slightly when pulled along the bias. The greatest stretch will be along the true bias.
Knit fabrics have a grain too. These fabrics are created by looping yarns together. Lengthwise loops create ribs (sometimes called “wales”) which can be seen on the right side of the fabric. Crosswise loops are called “courses” and they are loops that run across the fabric. This is typically where you will find the most stretch in a knit fabric. Which is important to watch out for when cutting out certain pattern pieces. A good rule of thumb: the greatest stretch should go around your body. Read our blog post about stretch percentage for some tips about choosing the right knit fabric for your pattern when considering the direction of greatest stretch.
Why is the grainline important?
Grainlines are important to follow because pattern designers have designed their garments to have a specific look and desired fit. If you ignore grainlines you could have a garment that is impossible to put on, the pieces might not fit together properly or the garment itself may not fall off the body in the intended way.
To make sure your pattern pieces are on grain, use a ruler to measure from the selvedge to the grainline all the way down your pattern piece. If the pattern piece is on grain the selvedge and grainline should be parallel to each other and the distance between them should be consistent all the way down the pattern piece. When you cut something off grain the threads are able to move more because they are no longer as stable which can cause the fabric to stretch in unwanted places. This is why stay stitching is important (read more here) especially for pattern pieces with curves (eg. armholes, neckline, sleeve head) or pieces cut on an angle.
When fabric is off grain this is also when you get that annoying twisted pant leg problem or a top where the side seam starts to shift and ends up in the middle of your back. If you’ve ever bought RTW, it’s very likely you have experienced this happening to your clothes. iykyk.
Sometimes pattern pieces will be intentionally cut on the bias because they require a bit of stretch to fit around a round part of the body eg. collar for a collared shirt or jacket. Bias cut dresses or skirts will hang differently with more natural swish because of the way the fabric drapes differently and hangs off the body.
Read our other quick tip about what you should do with the grainline on your pattern pieces before cutting your fabric here.
Any questions? Did we miss something? Feel free to comment or send us an email, we love to hear from you!