When Charles Frederick Worth designed gowns for the French Emperess Eugénie de Montijo in the mid 1800s he introduced a new cut to the bodice which caught the imagination of fashionistas. He devised 2 extra vertical seams to the bodice which replaced darts and gave a perfect close fitting cut which elongated the torso flatteringly and gave a beautiful profile to the wearer. It was the princess seamed bodice.
Princess seam refers to 2 vertical seams that are placed between the side seams and the center front, on the front and back bodices.
The seam is a combination of the armhole bust dart and the waist dart – these darts are manipulated and redrawn as the new seam. The bodice is cut into different panels incorporating the darts and then joined together. The seam travels through the widest part of the bust and then reaches the narrowest part of the waist. It continue down to the hem.
The princess seam can start from the armscye or the shoulder and end at the hem of the dress or waistline. It can be combined with the waistline seam but usually, in princess-style gowns, there is no waistline seam.
The princess seam is cut so that it has a convex shaped curved edge (outward) conforming to the shape of the bust and a concave curved edge (inward) fitting the waist. All in all, it can create a beautiful close-fitting cut for the bodice. It is flattering for almost all body shapes.
How to sew the princess seams
Make the pattern
First, make a paper pattern for your regular bodice. Mark the armhole bust darts and waist darts.
Draw the princess seam line on the bodice. You can use a french curve to draw the lines.
On the front of the bodice, the princess seam can be drawn over the bust point or at least within 1 1/2 inches near the bust point. For the back bodice mark the princess seam over or within 1 1/2 inches near the shoulder blades.
Cut it out.
Now redraw this with seam allowance along the princess seam line. You can add a 1/4 inch seam allowance.
Cut this pattern from your fabric.
Staystitch the edge. As you have a bias seam along the cut edge there is always the danger of it stretching out of shape. This distortion can cause the seam to sag on your body. You can reinforce and prevent the fabric edge from stretching by stay stitching just inside the fabric edge so that it would not go out of shape. This is a good dressmaking practice. Do this as soon as you have cut the pieces.
Finishing the fabric edges before sewing the seam
You can finish the cut fabric edges along the newly cut princess seam before sewing the seam. It is better this way than finishing after you have sewn the seam.
As most of the fabric edge of princess seam is cut on a bias, it will not fray as much. But still, if you are concerned finish the seam allowance with a zig zag stitch first after you cut the fabric panels and clip the seam allowance and then join the seam. Then use a lining so that the seam is not visible on the inside.
Clipping is a necessity and not an option when sewing princess seams. You can make small single cuts in the seam allowance using small scissors – this will spread out the seam allowance and keep the outside without puckers – the curve has to lie flat. Do this before sewing the seam. You can make clips or wedge shaped cuts (notches).
Ensure that you will not be cutting too much that you cut the stitching line.
Another option is to cut the fabric edges with pinking shears, as you cut the pattern pieces. Then clip the seam allowance.
Sew the seam
To sew the seam, keep the pieces rightsides together. Match the stitching lines perfectly and sew with a small stitch. Sew carefully along the stitching line you have made. It has to be accurately on the stitching line so that you get a perfect look on the front.
As you sew the seam line you may have to stretch the fabric to make them match perfectly. But not too much – this will again cause puckers.
After the sewing the seam
Press open the seam allowance. You can use a curved pressing surface to get the curves pressed.