The dress is made of thin cotton muslin. The lining is made of linen and it's completely hand sewn with linen thread. I'm wearing it over only a high waisted cotton lawn petticoat with shoulder straps, also hand sewn with linen. It's accessorized with greek style leather sandals and a shawl with painted borders at both ends. I achieved the length by joining two shawls like Jen did in her regency shawl post.
The dress without the shawl.
I looked through a bunch of portraits of ladies dressed in the Merveilleuse style when I was deciding the design. Eventually this portrait became the main inspiration for the bodice and sleeves:
And Juliette Récamier the inspiration for a slimmer skirt.
For patterning, I used the c. 1798-1805 morning dress in Patterns of Fashion as main source. I sewed the bodice lining together first and then mounted corresponding cotton pieces on top and back stitched them down from the right side.
The skirts seams were sewn together leaving them open from the top to allow the bib front to fall open. The center back is cartridge pleated and then the skirts whip stitched to the bodice and to a waist tape in front.
Then I made the v-neck front piece and attached it to the waist tape as well. The bodice closes with hooks and eyes and then the bib front is pinned to the shoulder straps after the waist tape ends are tied together in front.