Stitching Line
The line where the fabric pieces will be stitched together. When matching up pattern pieces or making pattern adjustments, it is essential to match or adjust the stitching line, not the cutting edge. In Commercial Patterns, it is usually 5/8 inch | 1.5cm unless otherwise specified. Between the stitching line and the raw edge is the seam allowance.
Examples
Image 1: In this example the stitching line has been marked with a dashed red line. The stitching line is 5/8 inch | 1.5cm from the raw edge. This gives the pattern 1.5cm seam allowance. Commercial patterns usually have the stitching line marked like this (except in black, not red). In the fashion industry the stitching line is usually marked with notches(see Image 2).
Image 2: This pattern is marked with notches (and drill holes). In the fashion industry, where there are corners (circled in red on the Bodice Back), it is common practice to mark only one seam-line - notching both corners weakens the pattern. When I first started making my own patterns, I notched all corners because generally I won't be using that same pattern over and over again. (Nowadays I don't notch at all because I always use 1cm seam allowance on all seams and don't need or use notches).
