Silk, for all its beauty, can be a difficult fabric to work with. Threads can pull and run, needle marks will show indefinitely and chalk can damage the fabric. Silk dresses usually use a narrow hem, as wider hems can pull and pucker due to the weight of the fabric. Many silk dresses use rolled hems, stitched either by machine or by hand. Rolled hems vary from 2 to 6 millimetres (1/16 to 1/4 inch), depending on the weight of the fabric.
Machine rolled hems
Install your rolled hemmer foot. Remove the standard presser foot from your sewing machine and replace it with the rolled hem foot. Practice using it with a scrap piece of fabric before moving on to your silk dress.
Fold and press the silk. For narrower hems, fold over less fabric, generally around 3 mm (1/8 inch). You will only need to fold and press the first 10 cm (4 inches) of your dress's hem, as the rolled hem foot of your sewing machine will take care of the rest.
Place the pressed hem under the rolled hem foot. The raw edge of the silk should rise over the curved edge of the foot to the left. The fabric will come between the two tines of the rolled hem foot, unlike normal sewing, where the fabric is completely flat under both tines. Once the fabric is in place, lower the rolled hem foot fully onto the fabric.
Begin sewing. Use the machine at a slow speed to ensure the fabric is rolling correctly. Check frequently to determine whether or not the fabric is forming a full tube around the rolled hem foot. You may need to pull the fabric gently over the foot as you sew to help the fabric stay in place.
Trim the fabric. Cut off any ravelled edges to give yourself a clean surface to work with. Trimming will also keep any loose fabric threads from sticking out of your hem.
Hand stitched rolled hems
For hand stitched rolled hems, thread your needle with a thread matching the silk dress fabric colour.
Roll a small amount of fabric between your fingers towards the wrong side of the fabric. Use the hand that will not be stitching to roll the fabric. The less fabric you roll, the smaller your hem will be. Create the roll as tightly as possible for a neat appearance.
Begin stitching. Sew through the fabric immediately behind the roll, and then through the top of the roll. Use the smallest stitches you can produce, and keep them as evenly spaced as possible. Repeat until you have hemmed the entire dress.