/cgl/ - Cosplay & EGL

>>9617261

And finally, an answer. This is from Reader’s Digest Guide to Sewing. The section you want is called grading seams.

Basically chiffon is so thin and sheer that if you cut and serge 3-6 layers of fabric (the chiffon, the underlining and the lining = 3 layers. The seamed areas s will have 6 layers because the seam is turned under there, so it lies under another set of layers), there will be an obvious bump or ridge showing where seam edges are, because chiffon is so thin. To avoid this, you need to cut the seams to different lengths and not serge them, that way it’s less obvious when 6 layers of fabric becomes 5, then 4, then just the 3. But then you’d have to leave the edges raw, and enclose most of the bodice to prevent the raw edges from fraying.

The lining is mostly sewn to the dress at the waist for this, the gap is probably the same as leaving a pleat in a jacket lining — ease for body movement so you’re not straining the dress everytime you shift the lining when you move your body.

The lining is also made from fray-resistant stuff to minimise fraying, which explains why it's cut that way at the zippers and allowed to remain unfinished

That’s why if you buy a chiffon dress, the bodice section will be mostly sealed off with raw edges inside, so the chiffon can lie flat and look good. The gap is for the lining to shift a little without yanking the dress fabric too much along with it.

And that’s why it’s so easy for me to post so many dresses with serged bodices, I just went through my wardrobe and picked out the dresses with heavier cotton fabric. They’re all serged because the fabric is thick enough not to show the seam edges, the chiffon/thinner fabric need to have raw edges so that they can grade the seams into different widths.