The main requirement for crime scene documentation is to provide a visible and long-lasting record of an accident or crime scene. With precise measurements of the locations and evidence, forensic photography aids in understanding the various aspects of a crime scene. By examining the photographs of evidence that were collected, forensic photography can, in some situations, assist prove the corpus delicti and the modus operandi and link the suspect to the murder scene. Using forensic photography, it is possible to prove every factor of a case and exonerate the innocent. By fully utilising forensic photography and sustaining a chain of custody, the judicial system may be able to comprehend and proceed cases more efficiently and precisely.
Alternate Light Sources (ALS)
Lasers, blue or green lights, and coloured filters are used in photography ALS to identify processed latent fingerprints or other concealed and unnoticed evidence. In forensic inquiry, the use of alternative light imaging for both identifying and documenting latent evidence is increasing dramatically. Serological fluids such as blood, sperm, saliva, various forms of ink used to counterfeit papers, bruises, or other pattern injuries left on the human body at the crime scene might be discovered with readily using ALS. ALS light sources are also utilised to analyse and identify bite marks, fingerprints, serological fluids, and white restorative materials such as composites.
Infrared (IR) Photography
Biological evidence, erased handwriting, and burnt papers may all be revealed using infrared photography, which also makes it possible to preserve charred documents and other types of secret content. IR also photographs gunshot wound remnants on clothes. Infrared light is used for image sensors or film for infrared photography. The wavelength used in infrared photography is between 700 and 900 nm. Evidence that cannot be seen with the human eye is photographed using infrared technology. IR light sources include quartz-halogen lamps, tungsten lamps, and flash units.
Ultraviolet (UV) Photography
Body fluids including blood, semen, perspiration, and fingerprints may be photographed using ultraviolet light on surfaces with a variety of color. UV photography is often done in three areas: UVA (315-400), UVB (280-315), and UVC (100-280). Certain substances absorb UV rays, while others reflect it. The subject is exposed to a UV radiation source, which the subject then reflects back into the camera. When using this method, it’s crucial to cover the lens with an ultraviolet transmission filter to stop any visible light from impinging on the typical black-and-white film. This uses a filter that blocks all visible light while allowing UV radiation to pass.
Oblique Light Technique
This approach employs one or more lights positioned at various angles. If just one light is being used, a white or silver reflector can be positioned on the other side of the evidence to reflect part of the light back toward the evidence. It helps in the elimination of shadows. Oblique lighting’s primary goal is to sharply illustrate the three-dimensional characteristics of the evidence with strong contrast to highlight pertinent depth.
When documenting evidence with glossy or reflecting surfaces, diffuse lighting is often used. To soften the light, an opaque substance is put between the light source and the subject in diffused lighting. It produces uniform illumination with fewer reflections and hotspots. The opaque substance might be as simple as a portion of a white bed sheet or an empty water bottle, or it can be a commercial gadget made specifically for laboratory photography.
RECENT ADVANCEMENTS IN FORENSIC PHOTOGRAPHY
Drones go by several technical names, including remotely piloted vehicles (RPV), unmanned aerial vehicles (UAV), and unmanned aerial systems (UAS). LIDAR (Light Illumination Detection and Ranging) technology, which is incorporated in drones, may be used to digitally map the whole crime scene by shining a highly coherent laser beam at the surface of the scene’s objects of interest. Drone programming can be controlled remotely or through ground-based control devices. It is especially helpful in crime scenes where there are hills, secondary crime scenes, or where there may be evidence on lower hills. Evidence is captured in photography in places like ponds, mountains, lakes, and slopes. In rural locations, woodland regions, or over bodies of water, it is possible to fly it to a high height.
► CAD Program
Forensic scientists can benefit greatly from computer-aided drafting (CAD) applications. One of its most straightforward and valuable applications is crime scene documentation, where they may be used to help create clean, clear line drawings of crime scenes. A CAD application may generate two-dimensional (2-D) drawings of the scene from one’s notes to scale as a demonstration assistance. The CAD/CAM computer system may be used to create a 3D-image of an object recovered from a crime scene by scanning the object and storing all of the information, which can then be used to evaluate the finding.
► Amped Software
This programme is used for picture and video analysis, enhancement, and authentication in forensic security, investigative, and military applications. The programme is used for authentication and the detection of any kind of modification. It mostly aids in determining if the picture has been edited or not.
It is beneficial to be able to view the concealed information and details. It uses a clone detector to determine whether or not the photograph or picture has been manipulated. It finds and highlights copied regions inside an image, does noise analysis, and uses an extremely basic separable median filter to separate the noise. It is beneficial to investigate specific alterations such as airbrushing, distortion, warping, and perspective corrected cloning.
► JPEG Snoop
JPEG Snoop is a window programme that examines the source of a picture to ensure its validity. It investigates and decodes the internal details of JPEG and Photoshop files. A digital photo has some secret information, which JPEG Snoop may reveal.
Ghiro is forensic software for digital photos and images. It uses an error level analysis to determine whether or not a picture has been modified.
It authenticates the digital photo. When an image is posted to izitru, standard checks are run to identify if it is an unaltered original from a digital camera.
The FotoForensics tool employs error level analysis to find areas of varying compression levels within a picture. It aids in determining whether or not the image has been modified.
► Adobe Photoshop
Adobe Photoshop enables forensic investigators to improve topic photographs while removing surrounding images. Color channels are used in the simple mathematical functions to aid in better subject visualisation. The fundamental idea is to enhance the topic image while subtracting one or more channels (colours) that are predominantly composed of background images. The colour photos are where the enhancing method performs best.