Any image adjustment that produces a ‘look’ characteristic of specific photographic or darkroom techniques. It can include infra-red effects, as created by infra-red film, a ‘polarising’ effect to simulate the results from using a polarising filter on the lens, a ‘tilt-shift’ effect to replicate the shallow depth of field of an extreme close-up and so on. Effects can sometimes be applied in-camera but are more likely to be added in software.