1. A method for contrast enhancement for digital images, comprising: filtering an original image having original color values, to generate a first filtered image corresponding to bright color values, and a second filtered image corresponding to dark color values; deriving local highlight multipliers by applying a highlight response curve to the first filtered image, the highlight response curve being a function of color value that increases from a response value of one, corresponding to a color value of zero, to a response value greater than one, corresponding to a maximum color value; deriving local shadow multipliers by applying a shadow response curve to the second filtered image, the shadow response curve being a function of color value that decreases from a response value greater than one, corresponding to a color value of zero, to a response value of one, corresponding to a maximum color value; deriving local offset values by applying an offset curve to the first filtered image; and processing the original image, comprising: subtracting the local offset values from the original color values to generate shifted color values; multiplying the shifted color values by the local highlight multipliers; and further multiplying the shifted color values by the local shadow multipliers, thereby generating a contrast-enhanced image from the original image.