PLATEANDFILM
The old ways of the image — ambrotype, tintype, and film-photography heritage.
From correcting a long exposure for reciprocity failure and converting ISO to EV to sizing a scan for print, scaling a historical ratio, and identifying a process from the object in your hand, PlateAndFilm pairs free hands-on calculators with clear, sourced history. Understand the plate, not just the picture.
Historical-Photography Calculators
Free tools for exposure, dating, and archiving — reciprocity & exposure calculator, ISO↔EV converter, print DPI & size calculator, dilution and collodion ratio calculators, and a photo process identifier.
Reciprocity & Exposure Calculator
Correct a metered exposure time for reciprocity failure — the long-exposure effect that made historical emulsions progressively less sensitive the longer the shutter stayed open
ISO↔EV Converter
Shift an exposure value between ISO ratings — translate a modern meter reading into the terms a slow, historical-speed emulsion actually needs
Print DPI & Size Calculator
Work out the print size a scanned plate supports at a given resolution, or the scan resolution needed to hit a target print size, in inches and centimetres
Dilution Ratio Calculator
Scale a concentrate-to-water ratio from your own reference source to a target batch or available-concentrate volume — plain ratio arithmetic, not a chemical formulation
Collodion Ratio Calculator
Scale a multi-part historical recipe ratio — from your own archival or reference source — proportionally to any target batch size
Photo Process Identifier
Answer a few questions about support material, surface, mount, and case to get a likely process match — daguerreotype, ambrotype, tintype, cabinet card, or carte de visite
Museum of Historical Photography
Wander an immersive, richly illustrated collection — the mirror-bright daguerreotype era, the glass and iron of ambrotype and tintype portraiture, the cabinet cards and cartes de visite that filled Victorian albums, and the roll film and cameras that carried photography into the modern age, each in its own gallery. Every entry, image, and fact is drawn from Wikipedia and Wikimedia Commons.
Tour the museum →From the Journal
Clear, sourced guides on identifying and dating antique photographs, reading exposure across historical and modern standards, the wet-plate collodion era, and archiving plates for the long term.
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.
Keep Learning
Plain-language explainers on the building blocks of historical photography — the processes themselves, the inventors who built them, the studio formats that carried them into ordinary homes, and the cameras and film that followed — everything you need to go deeper with confidence.
Visit the Learn hub →