I think the process is easy. Levels provides all basic functions. In the example file, i separated 3 steps which can be combined (invert, global gamma, channel specific ranges). May add an curve or HSL adjustment for fine tuning. Can be stored as asset or LUT for easy reuse on multiple images (of same film, age, and lighting situation). For more accurate results, try to find better black / grey / white points. color film negative.afphoto