Green and red are two of the more vibrant colors in the film. “We put a little more green into the swamps,” Richard relayed.

Variety noted that crimson hues are prominent in Emancipation‘s final battle scene, specifically present in the Confederate flag, the Union banner, and, naturally, in blood. This type of symbolism can be compared to the little girl in the red coat in the otherwise black-and-white 1993 film Schindler’s List.

Source: https://www.distractify.com/p/is-emancipation-movie-in-black-and-white