Anthony Thorne
In analog film photography, it was common practice to make black & white photographs with an orange or red filter in front of the lens. By applying filters in digital photography, Film Simulations continue this practice to control the look of the image.
A green filter absorbs and tones down red. It is especially suitable for portraits because it targets the redness of skin tones, making the tonality look natural by adjusting the brightness of lips, which are often too bright, with the rest of the body. Green filters are widely used in sunglasses, and they can adjust contrast without disrupting the relationships between colors, so can also be used for a wider variety of subjects beyond portraiture.