Douglas Sirk, a Danish director who first settled in Germany before coming to the USA, can be regarded as a master of melodrama. To be convinced you can watch « Magnificent Obsession » «  All That Heaven Allows » and «Written on the Wind », all of which are great movies.
In 1959, he released « Imitation of Life », his swan-song and a peak of the genre. It is a remake of the 1935 eponymous movie by John M Stahl, another German born director who shot the flamboyant « Leave her to Heaven », probably the first film noir in color.
The movie tells the story of Lora (lana Turner) who starts from scratch and gets to the top, sacrificing her love life. She is helped by Annie, a black woman that she hosts. Annie is a nanny, a secretary, a maid, a cook. They are both widows and have a daughter.
It's one more time the old from rags to riches and fame story but, this time it's about self-made women. The feminine incarnation of the American Dream and the specific problems it causes. The film plays on pairs : mother/daughter, black/white, rich/poor.
Let's not forget it's a melodrama. The spectator is moved, cries, heartbreaking scenes follow one another. Nevertheless, what Sirk tells us about America, about everyday racism, about social classes, very few « serious » movies dealt with it.
Sirk carries the genre to a boiling point. Lyricism and colors litterally explode, as well as a social and racial violence (at a time of Civil Rights Movement) rarely shown in cinema.
Beautiful America smiles with shining white teeth, the citizens are well dressed, well trimmed and combed, but you can see the knives behind the smiles. The beauty of Sirk's melodrama is that they are hyperrealistic and become bigger than life. His use of colors emphasizes the drama. Almodovar, among others, will remember the lesson.
At the heart of the story is the very American problem of the « white negroes », embodied by Sarah Jane. It is indeed very American to ignore the notion of « métis ». You are black or white, period. And what tells you who you are is not the color of your skin, but the blood in your veins. One drop and you're black and treated as such. Puritan obsession of a so-called purity.
Sarah Jane faces a real dilemma : should she deny her mother and have a chance to succeed or reveal who she is and see every door shut in her face ?*
The film is also remarkable because it's about women, and strong women. Men are merely extras. A female and black America, this was unusual at that time.
There are sometimes silly laughters and clever tears. Let's cry intelligently and watch « Imitation of Life ».

*if you are interested in the problem of « white negroes » you must watch « Band of Angels » by Raoul Walsh and « colors » by John Casavetes and read Kate Chopin's marvelous short story « Désiré's Baby ».