“Before there was PowerPoint, there were slides. Real ones. They were tiny, and tactile, and delicate, and kind of delightful.”
Paula was describing 2x2” slides produced using 35mm film. They were one of the the dominant visual aids for about a half century, from 1955 to 2005. But, they were preceded by larger 3.5x4” lantern slides, which were used for about a century, from 1855 to 1955.
A Wikipedia article about slide libraries contains a timeline for both of these visual aids, and a web page at the Library of Congress web site briefly describes the history and manufacture of lantern slides.
Suppose that you were trying to describe how coal bunkers on a famous steamship like the ocean liner RMS Mauretania were being built in 1905 by riveting together steel plates. A single lantern slide, like the one shown above from the Tyne & Wear Archives & Museums, was worth literally a thousand words.
Sometimes color even was added to lantern slides by hand tinting, like this 1922 view of a garden.
When I was a child, my father had an Argus C3 35mm camera. I remember watching Kodachrome color slide shows of family vacations and other occasions. Later I owned a series of 35mm single lens reflex cameras (the last being a Nikon F3).
I still have a collection of binders with vinyl pages full of slides that could be held up in front of a window or lamp, and viewed with a loupe or a linen tester. Planning a presentation began with review of existing slides using a slide sorter or light box.
Production of new 35mm slides for presentations at technical meetings was a long and painful process. Typically it began at least a month earlier. For example, the applied metallurgical research slide shown above (from two decades ago) contains a drawing (borrowed from a technical report) and three optical microscope photographs. The yellow chart area and orange background were self-adhesive plastic overlays added to the drawing. Each photograph was cut to size and then had a magnification scale marker added to it. Then the final artwork was photographed, and the slides came back from processing a week later.
Do I miss this long, convoluted analog set of processes? Not at all! Drag and drop digital editing in PowerPoint (or Keynote) is much faster and less stressful.