I have been a fan of Judith Martin (aka "Miss Manners") for quite a while! She's funny as well as informative!
She once fielded a movie question about evening gloves that I think you might enjoy from her book, "Miss Manners(R)' Guide to Rearing Perfect Children" (Penguin Books, 1984, Page 252):
(This isn't the outfit in question but it's as close as I could come!)
Dear Miss Manners:
Having watched a delightful movie with Loretta Young and Ronald Colman, we were stumped by the young people asking why Miss Young wore almost shoulder-length white gloves when in evening dress. Those of my age saw nothing odd in it, but the young people were truly curious as to the reason for such attire. Certainly it was not for modesty, for the dresses were extremely low-cut.
We do not mean to imply that your age is such that you would have worn such gloves, but think that you probably will know the reason, if anyone does.
Miss Manners is hurt that you think she would not have worn such gloves. You never know when you will insult people, do you?
The reason for the gloves is immodesty, a principle that young people, brought up to run about half-naked, do not understand. The idea is, the lower the dress, the higher the gloves. Miss Young very properly did not want to put on an extremely low-cut dress only to have people stare at there bare elbows.
. . .
Miss Maven wouldn't want just anyone looking at HER bare elbows, either!