Thanks to geogirl and her sweetheart neckline contribution, we have a new series! I am starting with my personal favorite, the portrait collar. Both flattering and regally dignified, I think this collar is under-utilized in the royal world.
I don’t know that there is an official designation for what constitutes a portrait collar, but I’ll do my best to describe what I believe it is. It’s a wide neckline that comes to a v-neck or a shallow scoop neck and often contains a stiff lapel. It frames the face. I feel that it flatters a range of ages, and isn’t too youthful or too mature looking for anyone.
We could debate the difference between portrait collars and shawl collars (which the Google tells me is a turned-over collar of a garment that combines with lapels forming an unbroken curving line), but for our discussion purposes let’s group them together. They both frame the face beautifully, in my opinion.
The Duchess of Cambridge wore this modified shawl collar from Jesire (a now defunct brand) during a visit to the National Portrait Gallery in 2012.
In 2016, the Duchess visited the Netherlands wearing this Alexandra McQueen suit with an offset semi-portrait collar. How I wish it hadn’t wrinkled because that neckline is perfect.
An exaggerated (and far more stylized) version of the portrait collar was worn by the Duchess of Cornwall in 2019, on a repeat Bruce Oldfield gown (first worn for Charles’ 70th birthday celebrations)
Now for the truly dramatic: Queen Silvia in her official photograph, wearing a Jacques Zehnder gown. This is a portrait/shawl collar done up in a grand fashion. The still lapel (or shawl) frames her jewels and face beautfilly. A completely regal look is achieved.

As you can see, using our definition this style can flatter all ages, and all types of garments from the businesslike to the dramatic. Spam your own examples of the shawl/portrait collar in the comments. Can’t wait to see them!