Definition
A princess seam is a long, curved vertical seam that runs over the bust point to shape a bodice, replacing darts and fitting bust, waist and hips in one line.
Princess seams are darts in disguise. Instead of folding out excess fabric in a short wedge, the bodice is divided into panels and the shaping is drawn into the seams between them, running smoothly from the shoulder or armhole down to the hem.
The two main versions:
- Shoulder princess: starts at the middle of the shoulder seam and passes over the bust point. Long and slimming, and easy to adjust over the bust.
- Armhole princess: starts in the front armhole and curves to the bust point. Common on dresses and jackets.
Princess seams are especially useful for fuller busts, because each panel can be shaped independently and a full bust adjustment can be made by adding to the side panel. They also make fitting a toile simpler: you pin the seams in or out exactly where needed.
To sew one, staystitch the inward curve of the center panel and clip it to the staystitching, then match the notches and sew with the clipped side up so it opens to fit the outward curve of the side panel. Press over a tailor's ham to keep the curve.
Unlike a dart, which you can only shorten, lengthen or move, a princess seam lets you change the shape along its whole length.