Irregular Webcomic! #710

Way back in the Dark Ages, cameras used to have this strange stuff in them called film. When you took a photo, the light hit the film and it recorded the image. Then you'd have to take the film to a business that used to be known as a photo developer, where you would have to pay money for them to take your film and turn it into photographic prints on paper. And you'd have to buy more film for your next lot of photos. And one film could only store up to 36 photos on it. And you couldn't download them off the film and if you wanted to put photos of your cat on your web site you had to scan them in!

Geez, we were bloody crazy back then.

Anyway, the most common sort of film actually stored the photo with all the colours reversed, as a negative image. How wacky is that?

2014-02-04 Rerun commentary: Negative film was turned into printed photos by a process of projecting light through the film onto special light-sensitive paper. The paper had chemicals in it which responded to light by changing their chemical properties. Then the paper had to be put into special solutions of chemicals to "develop" them. The chemical reactions caused the chemicals in the paper to change colour, becoming once more the negative of colour of light which was originally shone on the paper. Shine red light onto the paper, and you get green on the paper. This reversed the negative image in the film - if you photographed green trees, the negative film would show a red region, and then that red region would produce green on the paper when you printed it.

Way much more complicated than digital cameras and images!

But that's not the only type of film there was! There was also positive colour film (usually known as reversal film, since it was the reverse of normal print film), which when you took a photo of green trees would produce a green area on the film. This was no good for printing on paper, but it was good for projecting light through (using a slide projector) so that you could see the image projected on a screen. Positive (or "reversal") film was also called slide film, since it made slides that you could project.

So not only did you have to muck about with all this film stuff, you had to decide whether you wanted to make paper prints of your photos, or slides that you could project, and then choose your type of film before you shot the photos. If you chose regular (negative) film, you could have paper prints. If you chose reversal (slide) film, you could have slides.

You couldn't have both!

(Actually, you could if you wanted to pay through the nose. There were processes for turning slides into paper prints, and for turning negatives into slides, but these were expensive and rarely done. They often involved taking a new photo of the old photo, with the other type of film.)