One of the best ways to learn fine dress making is to study examples of the craft. This silk sheath dress from the mid-1950's is a great example. It is clearly a custom made dress, with many hand sewn details. By looking at it in detail, we can learn more about the design and drape of this wrapped 'sarong style' dress, along with tips on how to sew a feather weight dress like this that holds its shape well when worn.
This gorgeous navy dress of silk twill has a blue floral pattern that is probably Italian silk. It is backed by lining that is sewn 'in one' with the outer fashion fabric. I use the term 'flat lining' for this process. The lining is also used as a base to hold the drapery in place. It is probable that the customer had a fitting wearing the lining, while the dress designer wrapped the silk fashion fabric around the body, pleating it into the side seams as shown below.
The right and left sides are patterned and sewn differently, creating the signature sarong effect. This sarong skirt is sewn into the sheath side seam on the right, but it wraps around the left without a side seam, hanging open at the center back.
Looking inside the dress we can see the construction techniques. These are classic points. The scarf weight fashion fabric was 'backed' by a lining. The two layers were stitched together, then cut with pinking shears. When pressed open, the stitching shows clearly that this was 'flat lined'.
The transfer marks used to place the darts shows as little white dots. These would have been part of the custom or couture process. Seam tape is sewn along the waistline seam to stablize it and keep it from ripping apart. This tape was also used to edge the hem. Using hem tape is an easy way to provide a clean edge that is easy to sew through.
The bodice of this dress was cut with princess seam lines in the back, while the front had conventional darts. The fashion fabric was draped on top of this and sewn in place. This same lining was used in the skirt, but only to the knee level. This would keep the hips smooth, but allow the hem area to drape nicely.
This wonderful dress is listed in my shop on Etsy where you will find more photos of it. If you like this style, look for designs by Dorothy O'Hara, Helen Rose, and Peggy Hunt among others from that era who specialized in draped dresses. (this dress does not have a label)