You have your pattern picked out and you are on the way to the fabric store. Depending on what you're planning to sew, your pattern should tell you whether you need a woven fabric, a knit fabric or a stretch fabric. Each of these has its own set of qualities and properties. Understanding these differences and matching them to the kind of garment you want to make is important for sewing a successful project.
Straight of Grain Bias
A woven fabric has fibres running parallel to the selvedge (the finished sides of the fabric). These are called the Lengthwise Grain or the Straight of Grain. The fibres running perpendicular to the selvedge are called the Crosswise Grain. The fabric is held together by weaving the crosswise fibres over and under the lengthwise fibres. When the fabric is pulled in the direction of the lengthwise grain or the crosswise grain it stays quite firm without much distortion or stretch. When you cut fabric on the lengthwise grain it is an excellent choice for garments with structure. Things like button-down shirts, pencil skirts, A-line skirts, jackets, coats, trousers, etc.
When a woven fabric is rotated 45˚ it is called the Bias. The bias has quite a bit of natural stretch which encourages a lot of movement in the fabric and makes it a softer, flowing fabric when it hangs. Cutting fabric on the bias makes it a perfect candidate for more flowing, feminine silhouettes. Things like slips, camisoles, blouses and long skirts. It can also be used to change the orientation of a pattern. This technique is often used on the back yoke of plaid shirts. The bias is also used to make bias binding because it can easily be manipulated around curves and corners.
Knit fabric in a relaxed state Knit fabric being stretched
Knit fabric is created by continuously linking loops of fibre together. Because each strand in a knit fabric travels in a wavy line from side to side it has the ability to stretch quite far and then bounce back to its original shape. There are many ways that knit fabrics can be created. Sometimes the fabric can only stretch from side to side. This is usually called two-way stretch. Others can stretch both up and down and from side to side. This is usually called four-way stretch. If your pattern calls for a knit fabric there will usually be chart indicating how much your fabric should stretch. It's always a good idea to check and make sure yours is similar if you want to achieve the best results. Patterns designed for knits will often include a grainline. In the case of a jersey (a t-shirt fabric) you can see vertical ridges formed by the loops of the fabric. These lines indicate the grainline. Other patterns refer to the Degree of Greatest Stretch (DOGS). You can determine the DOGS by stretching the fabric in both directions and making note of the direction that stretches the most. If you were making a t-shirt you would want the DOGS to go around your body. It will stretch over the bigger spots and relax in the smaller spots. If you were to cut it in the other direction, the fabric would pull when it tried to fit around your body and it would stretch out lengthwise because of gravity. Knits are excellent for a somewhat relaxed, form fitting silhouette. Things like t-shirts, leggings, pencil skirts, sportswear, lingerie, etc.
Spandex (Lycra®, elastane) is a very elastic fibre. It can be used when making a woven or a knit fabric. A woven fabric with spandex in it will still behave like a woven fabric except the fibres themselves will stretch. A great example of this is stretch denim jeans. Often times stretch denim only has spandex in the crosswise grain. This helps the denim to stretch around the body, making movement and fit more comfortable. Keeping the lengthwise grain free of spandex helps the jeans retain their vertical shape. Knit fabric already allows for quite a bit of stretch. Adding spandex to a knit just make the fibres themselves stretchy as well.
Picking the right fabric goes a long way toward a successful garment. Hopefully this information helps you to decide what you need for your next project and why.
We've been talking a lot about prep work here on Sewing Notions but next time we'll be getting into the good stuff. It's time to lay out our fabric and start cutting it up.