PlateAndFilm
The Journal
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.
Scanning and Archiving Antique Photographs: A Digitization Primer
A practical starting point for digitizing daguerreotypes, tintypes, and card-mounted prints — resolution targets, handling, and storage that will hold up decades from now.
Reading ISO, EV, and Exposure in Historical vs Modern Photography
Modern meters are calibrated for ISO 100 or 400; historical processes run at ISO 1 or lower. Here's what that gap actually means for getting an exposure right.
Identifying a Photograph's Process: A Step-by-Step Key
Walk the exact decision tree our Photo Process Identifier runs — support material, the magnet test, and mount size — with the tool's real output at every branch.
Reciprocity Failure in Practice: Worked Exposure Examples
A run of real, calculated corrections — from a 1-second snapshot to a 2-minute interior — showing exactly how much extra time reciprocity failure demands, and why the answer isn't a flat percentage.
ISO and Exposure Value Are One Relationship: A Worked Guide
ISO and EV aren't two separate numbers to look up — they're one log-base-2 relationship. A set of worked conversions from our ISO↔EV Converter shows exactly how it behaves.
Sizing a Print From a Negative: A Worked Guide
One formula, run both directions with real numbers — what print size a scan supports, and how many pixels a target print size actually needs, across common historical plate and card sizes.
Why Victorian Portraits Look the Way They Do
Stern faces, hidden headrests, and children who look strangely still — the look of a 19th-century studio portrait traces back to a handful of hard technical constraints, not the sitters' moods.