page_title: Forensic photography
section_title: Analysis of historic photographs
hierarchical_section_title: Forensic photography / Analysis of historic photographs
caption_attribution_description: English: River Tay Bridge, middle section collapsed, photographed by Valentines in 1880
context_page_description: Forensic photography, also referred to as crime scene photography, is an activity that records the initial appearance of the crime scene and physical evidence, in order to provide a permanent record for the courts. Crime scene photography differs from other variations of photography because crime scene photographers usually have a very specific purpose for capturing each image.
  Crime scenes can be major sources of physical evidence that is used to associate or link suspects to scenes, victims to scenes, and suspects to victims. This is Locard's exchange principle. It is the basic tenet of why crime scenes should be investigated. Anything found at a crime scene can be physical evidence. In scientific crime scene investigation, the first activities at the crime scene are essential for the successful preservation of the physical evidence. The first responder and ultimately the crime scene investigator have the obligation to make the scene secure and ensure that any further activities at the scene do not change the evidence. The use of a multilevel security method would accomplish this task. The preliminary scene survey is the first on-scene activity.
context_section_description: Crime or accident scene photographs can often be re-analysed in cold cases or when the images need to be enlarged to show critical details. Photographs made by film exposure usually contain much information which may be crucial long after the photograph was taken. They can readily be digitised by scanning, and then enlarged to show the detail needed for new analysis. For example, controversy has raged for a number of years over the cause of the Tay Bridge disaster of 1879 when a half-mile section of the new bridge collapsed in a storm, taking an express train down into the estuary of the river Tay. At least 75 passengers and crew were killed in the disaster.
  The set of photographs taken a few days after the accident have been re-analysed in 1999–2000 by digitising them and enlarging the files to show critical details. The originals were of very high resolution since a large plate camera was used with a small aperture, plus a small grain film. The re-analysed pictures shed new light on why the bridge fell, suggesting that design flaws and defects in the cast iron columns which supported the centre section led directly to the catastrophic failure. Alternative explanations that the bridge was blown down by the wind during the storm that night, or that the train derailed and hit the girders are unlikely. The re-analysis supports the original court of inquiry conclusions, which stated that the bridge was "badly designed, badly built and badly maintained".
caption: Photograph of 1880 showing fallen Tay Bridge
exif: {}