French fries, French toast, French braid, French manicure, French rolls, French knots, French heroes in romance novels & even the French beans – all my favourites. Now the French seam stitch as well.
French seam is nothing but the normal seam done twice, in such a way that the cut edges are well hidden. It looks exactly like the normal seam from the outside but on the inside, another folded seam is seen, not the seam allowance as is.
In sewing the french seams denote something dainty, everything discreet – the perfect edge finish for seams.
It hides the underbelly of the seam allowance, the fabric cut edges, inside the fabric folds. It is a neat and inconspicuous seam without much bulk on the inside.
Experts swear by a french seam especially when sewing sheer fabrics. Some couturiers even do french seams on a sleeve -. I would not dare to do it on curves. But the french seam is one of my favorites for finishing cut edges in straight seam lines.
Where all would you use the french seam?
The french seam is usually made on light to medium weight fabrics. I would use it on side seams on blouses made in sheer fabrics like chiffon, organza, tulle, etc. On custom made dresses made by designers, you would find this finish inside because they know that in dressmaking inside matters as well as the outside.
On bulky fabrics this seam would make more bulk.
How to do a french seam
You have to make a clean cut of your fabric edges first and foremost – that is neatened up any stray threads on the cut edge. The following steps will give you a 1/4 inch wide fold which will encase the raw edges of the fabric, on the backside of the seamline.
Mark the seam line on the wrong side of one of fabric pieces 1/2 inch from the cut edge. (This will only be sewn in the 7th step. Ignore this marking for the next 5 steps.)
Keep the fabric pieces wrong sides together. Make a 1/4 inch seam . Checkout this post on seam allowances for details on how I make a straight seam all the time. Nothing too complicated -1/4 inch seam is made by keeping the edge of the zig zag pressure foot along the edge and stitching or use the edge joining foot
Trim the seam allowance to 1/8 inch. Trim any loose threads on the fabric cut edges. This cannot be emphasized enough. You do not want thread peeking from the cut edge to the face of the garment. I say from experience. Have you cut chiffon and made french seams , then you will know.
Press the seam to one side, setting the threads; remember not to iron but only to press. Ironing will stretch the seams whereas pressing will settle the seam and make the seamline stronger.
Bring over the fabric to the other side, so that now the seam allowance is enclosed. Ensure that the fabric is folded as close to the first seam as possible. Now the fabrics will be right sides together. Finger press.
Now stitch a seam line on the mark you have made earlier. This will enclose the cut edges and the first seam line inside the fold of the fabric and the new seam line.
How to sew a french seam on curves like the armholes
Yes, this is tricky. I cannot say from experience but if I am making one I would trim the seam allowance in the Step 3 as close as possible to the seam line as I could and also snip the seam allowance close to the seam (being careful not to snip the seam line).
Then turn the fabric to the other side and stitch the seam very close to the first seam as possible.
On tight curves, french seam is not recommended especially when done by inexperienced sewists as the seam will pucker.