Beautician Max Factor with his Invention, the Beauty Calibrator

beautician Max Factor with his invention, the beauty calibrator, a device designed to show which parts of a woman's face needed more or less make-up. It is the kind of image that turns a line in a history book into something you can actually see.

Photography has only existed since 1839, which means the camera-recorded past is a narrow window — and every surviving frame from it is a small act of preservation, whether the photographer knew it or not.

Inventors of this era worked in public, testing their ideas in streets and fields rather than laboratories, and press photographers loved them for it. Images like this one document how much trial and error sits underneath the technology we now take for granted.