One of the most important aspects of sewing and working with fabric and patterns is the grain line.
Grainline is the line that the threads of the fabric run in, and is observed differently in woven and knit fabrics. Fabrics like felt do not have a grain line and can be cut in any direction but materials like leather or real fur have “non-traditional” grainlines that are not hard and fast and change from one material to another.
With both woven and knit fabrics, the grain of the fabric runs in line with the selvedge (the edge) of the fabric. On woven fabric this is referred to as lengthwise grain or the warp of the fabric. On knit fabrics you can find the grain by observing the pattern of the knit – if you look closely you should be able to see little ridges that run straight in one direction and in the same direction as the selvedge – this is the grain.
With leathers it is recommended to consider rather how the leather naturally bends and folds (and how it would have moved on the animal) as well as considering the nap of the fabric – especially with suede type leathers, as you want all your pieces to run in the same direction (as you would a one-way print).
Some pattern pieces are cut on different grain lines. With woven fabrics you will find pieces cut either lengthwise (the warp), crosswise (the weft) or on the bias. With knits it is important to note the grain but also which way the fabric stretches too, as sometimes you may want a piece to stretch across the body, or down the body. You can cut pieces on the grain, across the grain or on the bias as well. Felt type fabrics can be cut in any direction which can be extremely handy for minimising waste.
It is extremely important that pieces are cut properly on the grain otherwise they will not sit or fall right – we’ve all had that t-shirt that twists after a couple of washes and then never sits straight and swings around the body, making it uncomfortable to wear. This happens when the fabric has been cut slightly off grain.
If something is cut “on the bias” it generally refers to the true bias, meaning it is cut on a 45 degree angle to the grain. Pieces that are cut on the bias allow woven fabrics to have a little more stretch and mould around the body than it would if it was cut on the grain. Bias is used for finishing necklines and armholes, creating draped areas like cowl necks and for making slinky skirts and slips. It allows more flexibility in the fabric and adds a edge of luxury. Bias can be more challenging to see if you are unfamiliar with it as it has a tendency to stretch and move out of shape easily if not stored flat. When you do cut something like a slip dress on the bias you should hang the fabric before hemming as the fabric will drop and you can end up with an uneven hemline.
In summary, understanding the grain line is an integral part of learning to sew. If you do not cut your fabric on the correct grain your garment will become misshapen and can be uncomfortable to wear – then all your efforts will have been in vain.
Post in the comments below if you have any more questions about grain line or want clarification on anything I have mentioned above – otherwise happy cutting and sewing!