Quote Originally Posted by Hexavalent View Post
This thread WAS about ortho film. Some had suggested filtration to render an 'ortho look' with pan film.

Subtractive?
Yes.
Apply filter(s) that are a minus type. When you filter for B/W you are not adding colour but subtracting (neutralizing/removing to whatever degree) the colour. A minus yellow (blue), minus magenta (green) or Minus red filter (cyan) or the combination of these would tend to get you close to ortho on a pan film.