Ah, bum pads...nothing like wearing a pillow around your waist to make your derriere look bigger! But should you *always* wear one if you're in 18th century dress?
Generally, we try to veer away from saying "always" and "never" when it comes to historical costuming. Every character, impression, event, dress, costumer has different needs and different intentions.
When considering your artificial rump enhancements, here are some things to think about:
Do you care?
I'm starting with this one because everyone has their own purpose and intention with putting on a historical costume. It's OK to wear whatever you want in whatever way you want to and have fun doing it. Some costumers are in pursuit of historical accuracy in portrayal, some in construction, and some are in pursuit of dressing up and having fun. All pursuits are valid. If you don't want to wear a split rump, pocket hoops, or a bum pad, it's totally your choice.
What decade or year(s) are you playing in?
If you're definitely into the hip and rump bolstering it's important to choose the right style for the specific time you're portraying. Prior to the 1770s, pocket hoops, panniers, and round hoops (for English gowns) were fashionable. The emphasis was on the hips. A set of kidney-shaped pads on each hip will do the job, or explore pocket hoops of various sizes, especially for Robes a la Francaise. (We have a very easy pattern on page 75 in the AD Guide).
In the 1770s, a rounder and softer silhouette comes into fashion. Hip enhancements fall out of fashion and the fullness moves to the back. If you're hanging out in the mid-1770s and pulling your Italian gown skirts up or wearing a polonaise, the split bum is the thing (pg 130, AD Guide), but rounder pillows on the rear also work very well for sack-back jackets and garments without deep, boned points in the back.
In the 1780s and early 1790s, the silhouette becomes full and round with a graceful, fluffy line over the hips and descending into the skirt. A large bum pillow like the one in Simplicity 8162 is great for these years.
What style of garment are you wearing?
I mention this a bit above, but it's a good idea to consider to style of gown or jacket you're wearing when deciding what padding you may need. If you're wearing a Robe a la Francaise of almost any decade, you'll want some kind of hip padding. If it's an early 18th century Francaise, it'll be a pretty wide hoop/pannier; if it's a late 18th century Francaise, the hip padding will still be there, but greatly minimized compared to before.
1770s Polonaises and Italian gowns love split rumps, which allow for the deep V down the back while bolstering the gathered-up skirts.
1780s Pierrot jackets, chemise gowns, and redingotes want for full, round pillows without a split in back.
It's a good idea to consider your full undergarments before making your costume. You'll ideally have all of these bits and pieces prior to jumping in to making the dress, and you'll definitely want to wear them when you fit your gown or jacket.
What social class are you portraying?
Ladies of fashion in any decade followed the trends, but working women didn't. If you're portraying a lower-class individual, skip the bum pillow. There are many depictions of working class women in unfashionably slim-looking petticoats, but you can also wear a simple quilted petticoat, which were common and functional for women of all classes.
We purposefully did not make any kind of skirt support for the working class wool English Gown in "The American Duchess Guide" to show that full and fluffy skirts were not always the norm. I wear just my underpetticoat (under my stays), one wool petticoat, and the English gown in that chapter (pgs 14 - 69).
-------------------------------------
I hope you found this article useful. If you're looking for more direction on what to make and how, do have a look at The American Duchess Guide to 18th Century Dressmaking - we have patterns and instructions for making an underpetticoat, side hoops, and a split rump, along with how to wear each of these understructures. You can get a copy here. Also check out our Simplicity sewing patterns for underpinnings here.