French pleated drapes also known as triple pleated drapes or a fan pleat. French pleated curtains are very elegant and with a bit of practice you can become an expert pleater.
Decide how deep each pleat will be by experimenting with fabric. Take a section of fabric an inch in from the left hand edge. Make a ½ inch fold to the left and pin it in place. Next to the first fold, make another ½ inch fold, and pin them both down. Make your third fold. Unpin folds one and two and pin them together perpendicular to the fabric in a triple fan shape or French pleat. You may want to play around with different depths of material so you know how much fabric you will need to make the right size pleats.
Now that you know how much fabric you will need for a single French pleat, determine how many pleats you will need to cover the width of your window. Normally pleats should be 4-6 inches apart. Take your fabric measurements after you know how many pleats you will need in between. Do not forget to include the edge pleats. Add fabric per panel to the width for 2 inch side seams and 8 inches to the length for a 4 inch header and a 4 inch hem.
Make your basic curtain by sewing the two 2 inch side hems, raw edges turned under from top to bottom. Turn the top edge down. Before sewing it closed, insert a light piece of pellon or buckram to stiffen the header. Turn the raw edge under, stitch along the bottom of the header hem. Complete the bottom hem the same way, just eliminate the buckram.
Start making your French pleats following step 1. Pin the top of the pleat ½ inch from the top of the header. Go down 4 inches and pin the bottom of each pleat. This will accentuate the depth and folds of each pleat. Adjust the fullness across the width of the fabric. Once you have the right depth and width for your pleats, put a stitch at the top and bottom of each pinned pleat. This will help secure your pleats. Continue across the width of the curtain, until the end is reached. Repeat process for all other curtains.
Insert pleat hooks on the back of your drapes behind each pleat and hang your drapes on a traverse rod.