N is for Negative – #AtoZChallenge – 2020

N is for Negative

The negative. For those of you too young to remember, it used to be when you got a roll of film developed, you’d get a pile of prints plus the film from which the prints were made. But the image on the film was the opposite colors from real life. Reds in real life are green on the negative. Dark places are light on the negative.

Why are they reversed?

Photographic film itself is a thin strip of plastic upon which is coated some light sensitive chemicals. There are complex layers of chemicals each sensitive to different colors (for color film), or more simply sensitive to light and dark for black and white film. When these chemicals are exposed to light, they become darker. Thus, the brightest areas in the scene will be the darkest on the film.

This same sensitivity of greater light making for darker exposed chemicals is fine, because the printing process works the same way. Bright patches on the negative will become dark on the print. The reversal of color and brightness from scene to negative will be undone from negative to print.

A: The scene to be photographed; B: A color negative of A; C: The scene in black and white; D: A negative of picture C. Credit: rjt CC By-SA 3.0

See the other 25 letters of the 2020 A to Z challenge from Animal’s Place by clicking here! All about how cameras work!

Published by paleololigo

Scientist (Paleontology, Geochemistry, Geology); Writer (Speculative and Science Fiction, plus technical and non-technical Science); Mom to great boy on the Autism spectrum; possessor of too many hobbies.

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