This is a topic I've touched upon before, but amazingly have never dedicated an actual post to.
Dressing vintage can sometimes present problems for the large of boob, with many styles from the 1930s-60s featuring high necklines, ruffles, frills, and all those things we've always been told to avoid like the plague. It's unfortunately very easy for the large-breasted to end up looking dreadfully matronly in styles which our smaller-chested sisters can carry off looking breezy and fresh. So, I've put together my style tips for dressing vintage and avoiding the pitfalls - this is by no means a definitive list, but it's the one I live (dress) by.
The Right Support
In vintage as with any other fashion arena, the right undergarments are of paramount import. I favour bullet bras both for the vintage silhouette and the 'minimising' effect that the shape creates by not allowing the breast to bulge out sideways.
Vintage bullet bras in large cup sizes are near impossible to find, and modern reproductions like What Katie Did only go up to an F cup. The Doreen bra by Triumph gives a good vintage silhouette, I've heard, and is available up to a J cup in some styles.
Choose your Neckline Wisely
You'll probably have read the advice that the most flattering necklines for a full bust are V, scoop and sweetheart necklines. These help break up the expanse of chest. Go for a medium V neck - a deep V is both un-vintage and a little too sexy. The good news is that although a Peter Pan collar is out, sailor collars are a go.
As I mentioned in my knitwear post, vintage and vintage-style knitwear very often comes with a high, round neck. Other styles were worn though, so you don't need to worry about looking inauthentic if you choose something a little more flattering to your figure.
Define Your Shape
Wrap tops and dresses are flattering to pretty much every figure type. They accentuate the waist and divide the bustline - an overall win. A camisole top underneath can be helpful if the wrap doesn't close tightly enough.
Tailoring is also key. Avoid waist-length boxy jackets, which will make you appear square and shapeless - though even shorter bolero jackets can be an exception, as they allow a fitted waistline to show. Choose fitted jackets with a deep V and small lapels, cut to hip length. The length elongates the legs and the V divides the chest.
I'm a huge fan of dresses with a fitted midriff section and pleats or shirring to give fullness to the bust. Gathered and ruched fabric over the bust is flattering because it gives the impression that the garment is looser - the opposite effect of having fabric straining across the chest. Lucky for this style was massively popular in the late 30s - early 40s, and can be also be seen in some shirtwaists of the 50s.
Create an Illusion
Sometimes - say, in winter for example - the idea of wearing a plunging neckline might not be so appealing. But you can still use the principle of breaking up the expanse. Try sweaters with a contrast yoke or false V-neck. Layer high necklines under V or scoop necklines. Break up the expanse of chest with a statement necklace or a scarf.
Find a workaround - or wear it anyway
If you're still desperate to wear a style less suited to your figure, it may be possible to find a workaround. For example, if you've always admired those sweet little Peter Pan collars, try wearing a detachable one as a necklace with a scoop neck.
There are also ways to minimise the unflattering effects of high necklines. Even just having sleeves can make a difference: A sleeveless turtleneck may look gamine and playful on the small chested, but when the bustline is the widest point it only serves to draw attention and amplify the size. Long sleeves help to balance the look. Better still, layer it under a pinafore (jumper) dress.
When it comes down to it, if you love something just go ahead and wear it - rules are made to be broken!
PS: If anyone would like to contribute a guest post on how to flatter a smaller bust in vintage I'd be delighted! I'd have a go myself, but since it's not my area of expertise I'd love to pass the baton to someone better versed in the topic than I.