As promised, here's more about how the mantua-makers of Colonial Williamsburg recreated a 1770 gown belonging to Mrs. Thomas Newton.
A lady's gown was custom-made for her. It was created by draping, cutting, and pinning directly on her, and before any of that could take place, she needed to be wearing the proper underwear to give her a fashionable conical shape. In the first picture above, Sarah (apprentice mantua-maker, here standing in for Mrs. Newton) is wearing her shift, stays (corset), and pocket hoops, tied to her waist to support her gown at the hips. She's also wearing a kerchief at her neck that will be removed in later pictures.
In the second picture above, Sarah has pinned the first "piece" of the gown, the stomacher, into place onto her stays. Most 18th c. gowns were constructed of components like this, and pinned together with straight pins rather than permanently stitched. Not only did this allow for changing sizes (you know, fat days), but like modern separates, the different pieces could be swapped around for a variety of "looks."
In the third picture above, Sarah has tied on the gown's petticoats – what we'd think of as skirts - that will form the lower part of the gown. Now you can see how the pocket hoops give the petticoats structure, and that stylish wide-hipped look.
The last picture right, shows Sarah from behind, with the petticoats tied in place. Note that she's wearing her stays over her shift, not bare skin. Note, too, that the stays are spiral-laced in a zig-zag rather than criss-crossing, and fasten at the top with a knot rather than a bow.
That's two-thirds of the gown - more to come tomorrow!
Due to a software glitch, the photos in this post would not enlarge. For those of you who wish to see more detail, I've reposted them on my own blog here.