I can't quite remember the name of this movie. Somewhere before 2010 but is probably older than that. It was either on Encore channel or HBO. I can only remember the film being very clockwork/steampunk themed with the robots or characters being all 3-D animated but the girl is live action. She dresses like a tomboy. At one point an older girl presumably her sister, brainwashed her somehow into putting on makeup and a dress.
This sounds something like MirrorMask, a Neil Gaiman-written movie from 2005. The main character, Helena, is pretty tomboyish and towards the end of the movie is hypnotized/brainwashed by an older woman (her parallel-universe "mother") into believing she's a princess. The movie uses a very consistent yellowish tone throughout the bulk of the runtime, resembling a mix of sepia-toned footage and the dull glow of sodium lamps, and there's a great deal of intentional haziness or heavy film grain for stylization purposes.
Helena and a few other characters are portrayed through live-action, while most of the rest are CGI, so that fits with your recollection. One character, Valentine, wears a mask that hinders facial expression and makes him look somewhat robotic but he's flesh-and-blood, so that's a slight difference.
This site has a bunch of pictures and a summary that might help ID the movie as what you're looking for.