It's invite-only...

The women include Frida Kahlo, Sally Ride and Ida Wells

It lets you combine up to 10 photos and videos into a single post

You can now also mention friends and add links to your Instagram Stories

And no, it has nothing to do with pulling your trousers down... 

A study found that people with depression were likely to use Inkwell, the black-and-white filter

The clever app links your Spotify account with your dating profile and matches you with like-minded listeners