Category
Process History
How to Identify a Daguerreotype, Ambrotype, or Tintype
The three great direct-positive processes of the 19th century look similar at a glance but differ in support material, surface, and weight — here's how to tell them apart by eye and by hand.
Understanding Reciprocity Failure in Historical Photographic Processes
Why a light meter's straightforward math falls apart on a ten-second exposure, and how photographers working with slow historical emulsions correct for it.
The Wet-Plate Collodion Process: A Historical Overview
How a syrupy nitrocellulose solution, patented in 1851, became the dominant photographic process for two decades and gave the world the ambrotype and the tintype.
Dating Antique Photographs by Card Mount and Studio Format
Once photography moved to paper prints on card, the size and style of the mount became one of the best clues to when a photograph was made.
From Silver Plates to Celluloid: A Timeline of Early Photographic Film
The path from a one-off silvered plate to a roll of flexible film you could load in daylight took half a century of overlapping inventions — here's the timeline.