One of the most important concepts to learn as a beginner sewist is understanding the grain line. Whether you are working with woven or knit fabrics, the direction you cut your pattern or fabric in affects how your garment fits, stretches, drapes, and holds shape over time. Let's discuss it!
What is a grain line?
The grain line refers to the direction of the threads in the fabric. All fabrics are made from fibers that run in specific directions. If you have ever used a pre-made pattern, the long arrow that is often printed on each pattern piece indicates the grainline. This arrow is telling you how to lay and align your pattern pieces with your fabric before cutting. Ignoring grain lines can create twisted seams, poor fit, distorted shapes, sagging, etc.
Grain lines in woven fabrics and what they mean
Length/Straight Grain (Warp) - This grain line runs parallel to the selvage. The selvage is the perfect line that runs along the both ends of a fabric roll, and it is woven tightly.
- The strongest grain in the fabric
- Should run vertically against the body
- Holds its shape best (no stretching, no warping)
- The most common grain alignment direction (The arrow on your pattern piece)
Cross Grain (Weft) - This grain line runs perpendicular to the selvage.
- Used for print effects when the pattern allows for it
- Has slight stretch
- Runs horizontally against the body for slight stretch and comfort in fit.
Bias - The bias is a 45 degree angle (diagonal) between the length/straight grain and the cross grain.
- Has the most stretch and drape
- Garment will move and walk softer and bouncier
- Used to create a contour against the body
- Often used for flowing silhouettes (Slip Dresses, Skirts, etc.)
- Uses more fabric (since it runs diagonally), so garments must be priced higher
Grain lines in Knit Fabrics
Knit fabrics behave differently from woven's. Instead or warp and weft (Vertical, and horizontal thread lines), knits have lengthwise direction and crosswise direction. Stretch allowance in knit fabrics are often categorized in two ways: 2 way stretch and 4 way stretch
2 Way Stretch Knit Fabric
- Lengthwise direction has little to no stretch
- Cross wise direction has most stretch
4 Way Stretch Knit Fabric
- Lengthwise direction has great stretch (Same as cross wise)
- Cross wise direction has great stretch (Same as length wise)
Grain lines are the foundation of good and professional construction. Take the extra time to make sure your grain is aligned correctly, and it will significantly reduce mistakes and funny warping in your seam and hemlines. For more direction on identifying grainlines, Choosing fabrics that best fit your project, etc., book a private lesson with me. Hope you learned a lot! More soon!