I haven't planned on stocking several colours right at the moment, though it is certainly an option for the future - I need to see first how much interest there is on the market, and then I can decide to stock up and get some of the ribbon dyed. If you have a special colour in mind and don't need it fast, though, you can contact me and I'll see if I can slip it into one of Sabine's dyebaths...
Yes, of course. The young lady in question is called a bathing girl("Bademagd" in German), meaning somebody who is helping in the (sauna-type) bath. That is why she's carrying a pail of water and the sauna-frond for massaging the skin.
The picture comes from one of the early bible translations into German, the "Wenzel Bible", written and illuminated about 1389 to 1400.
The garment is surely an underdress; unfortunately, the only extant garment in this style, recovered in a Thuringian castle, got lost between its discovery in the 19th century and today. By the way, there are descriptions in some (also earlier) medieval texts that clearly describe see-through garments made of very, very fine cloth, so that is no singular occurrence. After all, medieval people were humans too and liked to see something nice!