Princess Seams - Sewing & Drafting a Smooth Princess Seam

Princess seams will not only make your bodice look beautifully fitted, but you will feel like royalty as you stand out among the crowds with a classical line of couture. The princess seam or princess line dates back to the 1880s and was named in honor of Alexandra, Princess of Wales. This new style at that time was created because the princess seams did away with the horizontal waist seam and bust darts.

Princess Seams Tutorial

What is a Princess Seam?

Princess seams are found on fitted styles of dress or top. They have two vertical seams on the bodice front and back. The princess seam replaces the bodice darts you will usually see, which create shape in the bust and waist.

Here is a typical example of a princess dress seam.

This fitting in a princess seam incorporates the length of the garment. It runs from the armhole or shoulder through the bust, down past the waist, and all the way to the hem. Here you can see the princess seams starting from the bust vs starting at the shoulders.

Princess seams add shaping to blouses, fitted bodices, and shirts. They are very flattering and often used to make elegant bridal gowns and evening wear. 

How to Sew Princess Seams Step by Step Instructions

Precision and perfection come to mind when you consider sewing a princess seam. Here are the steps to complete princess seams.

Step 1 - Cut and Match

Cut out and mark your pattern pieces according to the pattern. You should have a center bodice piece and two side panels. The same will apply to the back. Carefully mark any notches or markings. 

Step 2 - Stay Stitch the Edges

Stay stitch each piece along the curved edges to help with the stability of the fabric. Stay stitch with a small stitch length and stitch just inside the seam allowance line.

Step 3 - Pin & Ease

Pin and ease a side panel to the front panel. Start by matching the notches with a horizontal pin. Match the center point of the seam with the center point of the panel between the sewing notches, and then ease in on either side of the panels. Ease and pin all along the seam. 

Cut straight snips along the way if necessary to help ease the curved edge to the straight edge. Make sure you do not cut the stay stitching.

Step 3 - Stitch the Seams

Stitch your princess seam on the stitching line. Remember to back stitch or lock stitch the beginning and end of the seam. Stitch both sides.

Step 4 - How to Finish Princess Seams

Before you finish any seams, be absolutely sure you are happy with the fit of the garment. A princess seam is difficult to alter if you have already cut and neatened the seam.

There are several ways to neaten princess seams if you are not lining the bodice.

• SERGER - If you have a serger, then go ahead and use your serger to neaten the seams.  Press seams to the center when complete. 
• ZIG-ZAG - Zig zag stitch is a common seam finish for sewers that just have a regular sewing machine. Finish the seams either separately or together.
• FRENCH SEAMS - It is possible to use a french seam finish if your bodice has gentle curves. You would need to plan ahead for this.

Step 5 - Press

Press your seams towards the center front or the center back of the garment.  If you are lining the garment, you can press the seam open. For lined garments, it is not necessary to neaten the seam.  

Using a pressing ham to get the seam to open out neatly makes all the difference between a puckered seam and a smooth seam. Repeat the process on your fabric lining.

Tips for Sewing Princess Seams

1. MATCHING CURVES - Don’t expect the edges of the fabric to match at the top and bottom of the seam. The stitching line should match to make the seam straight. There will be a small triangle of fabric sticking out at the end of the seam. This will disappear when you neaten the armhole or set in a sleeve.
2. PRESSING - Use a tailor’s ham to press princess seams. A rolled-up towel can do the same job to get a deep press into the curved seams.
3. PIN FIRST - Use lots of pins or baste the seams at first. As you gain confidence, it is possible to sew with no pins and ease into the curves along the stitching line.
4. MAKE A MUSLIN - Make a mock muslin bodice to get the measurements correct for your body type. 

How to Draft Princess Seams

This principle for altering a darted pattern can be used to create a princess seam from the shoulder or from the armhole edge. Create princess seams into the back of the bodice pattern in the same way.

Step 1 - The Sloper

Start by using what is known as a ‘sloper’ bodice pattern. It is a basic, straightforward bodice pattern with a round neckline and two darts - A waist dart and a bust dart. By adjusting the pattern, you will remove the darts and convert them into a princess seam.

Step 2 - Mark the Princess Darts

Measure and mark the center point of the armhole or shoulder on the pattern. Draw a line from the center point through to the bust point at the waist. Extend the bust dart point to the line. This intersection is the new bust point. Draw a notch or line 2 inches above and below the dart point.

Step 3 - Cut the Princess Seam Pattern

Cut along this vertical line you have drawn. This is the new princess line. You will have two pattern pieces - a center front panel and a side front panel.

Cut along the lower edge of the bust dart to the bust point. Lift this edge to the upper line of the bust dart and tape it in place, leaving a slight gap of ⅛” at the bust point. Smooth the curves.

Step 4 - Mark the Pattern

Draw straight fabric grainlines for each pattern piece. The center front fold line acts as the grainline for the centerpiece. The side front grainline runs perpendicular to the waist edge. 

Step 9 - Seam Allowances

Add seam allowances to your new princess seam lines.

How to Adjust Princess Seams

The princess seam is designed to fit perfectly over the bust and into the waist.  If the seam is not fitting beautifully, there could be issues with the fullness of the bust seam or with the apex position of the seam. Alterations to the pattern will be needed before the seam can fit properly. 

Although every pattern has standard sizes, every body is unique, and there could be some unwanted wrinkles that need to be sorted out before you get to work on your expensive new fabric.

The best way to get an accurate fit is to make a muslin version of the pattern and alter it before you go cutting and pinning your expensive fabric. 

Adjusting Fit on Princess Seams

Here are the steps to take adjust princess seams on a muslin:

• Make up your muslin bodice according to the pattern. Put a zip in the back just to be sure you have the back closing neatly.
• Take a marking pen and mark the exact point of the bust apex. This is the tip of where the fullness of the bust is required.
• Use a seam ripper to open the seam where it is not fitting correctly. Open the seam enough on each side to see the stress lines disappear. These are the lines that appear to pull across the bust or sag under the bust because the princess seam does not fit properly.
• Place a piece of muslin fabric, inside the opened seam and adjust to fill the gap, and correct the width. 
• Remove the muslin and press the seam down the center. Cut through this line to create the two new pattern pieces making the necessary changes to fit your bust type. Add on seam allowances because these sides and front pieces will be a completely new pattern.

Fullness on Princess Seams

How to add fullness on princess seams on the pattern piece:

• On the side panel piece, draw a fuller curve. Measure the additional width at the fullest point, the apex of the bust. Graduate the fullness above and below the apex of the bust on the princess line.
• Take the center bodice panel and measure a new line across the pattern. Draw this line perpendicular to the waistline from the apex of the bust across to the side of the middle of the center front. Cut this line across the pattern piece and spread it open. 
• Measure a strip of paper exactly the same width as the amount measured and added to the curve at the widest point you added onto. For example, if you increased the curve by ½ inch at the bust apex point, then the width of the center bodice will increase by ½ inch.
• Tape the extra strip of paper into the space cut across the center of the bodice. This added strip should correspond with the side panel allowing extra fullness for the bust measurement. Remember, on the princess line, the side panel curves, and the center panel is straight. The fullness added to the curve needs to be complemented by adding it into the center of the bodice as well.

To reduce the fullness, follow the same method. This time reduce the curve and cut the center piece in the same way as before but overlap the pieces to reduce the length of the center bodice and make the princess seam smaller.

Adjusting the Apex on Princess Seams

What to do if the apex or the point of the bust measurement is too high or too low:

• Line your center front and side panels up on a piece of paper and draw a rectangle over the apex of the bust pattern for each piece. Use your notches to help line up the pieces. 
• Cut out the two rectangles and slide them up or down on the paper to set the apex or the bust point higher or lower on the pattern. Do the same adjustment for each piece.
• Redraw the seam adding in either above or below the apex point depending on how much you needed to raise or lower this point to suit your body type.  The important thing to remember is to move each side of the bodice pieces in exactly the same way.

Princess Seams - In Conclusion

Once you have mastered princess seams and fitted your pattern to suit your own figure you will have a pattern and design that is fit for a ball. Your gown will fit like a dream, and you will be the belle of the ball wearing a beautifully made garment following the princess line.