Editing Film stock (section)

===Chemistry===
Development chemicals applied to an appropriate film can produce either a positive (showing the same densities and colors as the subject) or [[Negative (photography)|negative image]] (with dark highlights, light shadows, and, in principle, complementary colors). The first films were darkened by light: negative films. Later films that produce a positive image became known as [[reversal film]]s; processed transparent film of this type can be [[Movie projector|projected]] onto a screen. Negative images need to be transferred onto photographic paper or other substrate which reverses the image again, producing a final positive image. Creating a positive image from a negative film can also be done by [[Image scanner|scanning]] the negative to create a computer file which can then be reversed by [[software]].