“Marie Curie: The Courage of Knowledge” is all grace. Filled with soft colors, a delicate score and a subtly compelling lead performance by Karolina Gruszka (“Salvation”), the story drifts gently through the brilliant scientist’s life, floating along through her most intimate moments. We follow Curie through the death of her husband, her greatest discoveries, her eventual affair and her lifelong struggle to be recognized by the brutally male-dominated scientific community. Gruszka’s Curie is icy, her face impassive and unreadable but for a few moments of raw emotionality that peek through the necessarily hard facade. There’s a quiet vulnerability to her performance that grounds the otherwise airy and ethereal film. But there’s a fundamental dissonance at the heart of the movie. “Marie Curie” has a lot it wants to say about love, curiosity, science and life’s trials — but it’s so self-consciously artful that it ends up saying very little at all. It’s a very pretty film, but its substance is lost in all the paper-thin, gossamer beauty.