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Forensic colorimetry, or forensic color analysis, is the examination of specimen color for purposes of forensic investigation. Typical specimens involved in color analyses include pigments, dyes, or other objects that are distinguishable by their intrinsic color. Analyses may be conducted by-eye or by computational methods, both by matching specimen colors to a standardised chart or database.
There are numerous quantitative and qualitative methods that an investigator may employ to analyse specimen color.
Color analysis can be conducted by-eye, usually matching specimen color with reference charts. This methodology has been used extensively in soil analysis, often using the Munsell color system as the reference. [1] [2] While this is a traditionally used method, it is considerably subjective, relying on the ability of the naked eye to match colors.
Spectrophotometers are devices that measure the light absorbed or transmitted by colored objects. [3] More recent developments have led to advances in handheld spectrophotometers, which allow comparisons between sample color and database colors without the need for multiple pieces of equipment. These devices are most practical for analysing colors on a flat, homogeneous solid surface.
Where a heterogeneous specimen, such as a soil or powder, requires quantitative analysis, digital photography may be used. This method has successfully been demonstrated in forensic soil analysis, using the Munsell colour system. [4] A similar method has been applied to nuclear forensics, for the quantification of uranium oxide powder color. [5] Both methods report suitability for use by both experts and non-experts alike, as the methods only require a camera on site. A drawback of this method is in the lack of centralised databases for color matching.
Forensic palynology is a subdiscipline of palynology, that aims to prove or disprove a relationship among objects, people, and places that may pertain to both criminal and civil cases. Pollen can reveal where a person or object has been, because regions of the world, countries, and even different parts of a single garden will have a distinctive pollen assemblage. Pollen evidence can also reveal the season in which a particular object picked up the pollen.
In colorimetry, the Munsell color system is a color space that specifies colors based on three properties of color: hue, chroma, and value (lightness). It was created by Albert H. Munsell in the first decade of the 20th century and adopted by the United States Department of Agriculture (USDA) as the official color system for soil research in the 1930s.
Forensic dentistry or forensic odontology involves the handling, examination, and evaluation of dental evidence in a criminal justice context. Forensic dentistry is used in both criminal and civil law. Forensic dentists assist investigative agencies in identifying human remains, particularly in cases when identifying information is otherwise scarce or nonexistent—for instance, identifying burn victims by consulting the victim's dental records. Forensic dentists may also be asked to assist in determining the age, race, occupation, previous dental history, and socioeconomic status of unidentified human beings.
Spectrophotometry is a branch of electromagnetic spectroscopy concerned with the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. Spectrophotometry uses photometers, known as spectrophotometers, that can measure the intensity of a light beam at different wavelengths. Although spectrophotometry is most commonly applied to ultraviolet, visible, and infrared radiation, modern spectrophotometers can interrogate wide swaths of the electromagnetic spectrum, including x-ray, ultraviolet, visible, infrared, and/or microwave wavelengths.
The post-mortem interval (PMI) is the time that has elapsed since an individual's death. When the time of death is not known, the interval may be estimated, and so an approximate time of death established. Postmortem interval estimations can range from hours, to days or even years depending on the type of evidence present. There are standard medical and scientific techniques supporting such an estimation.
Forensic identification is the application of forensic science, or "forensics", and technology to identify specific objects from the trace evidence they leave, often at a crime scene or the scene of an accident. Forensic means "for the courts".
Bloodstain pattern analysis (BPA) is a controversial subjective practice that consists of the study and analysis of bloodstains at a known or suspected crime scene. This is done with the purpose of drawing inferences about the nature, timing and other details of the crime. It is used mostly to study homicide or other violent crimes in which blood is present and is claimed to help in crime scene reconstruction. Since the late 1950s, BPA experts have claimed to be able to use biology, physics, and mathematical calculations to reconstruct with accuracy events at a crime scene, and these claims have been accepted by the criminal justice system in the US.
An electrostatic detection device, or EDD, is a specialized piece of equipment commonly used in questioned document examination to reveal indentations or impressions in paper that may otherwise go unnoticed. It is a non-destructive technique, allowing further tests to be carried out. It is a sensitive technique capable of detecting indentations on pages several layers below the top sheet and many years after the indentations were created.
Calliphora vomitoria, known as the blue bottle fly, orange-bearded blue bottle, or bottlebee is a species of blow fly, a species in the family Calliphoridae. Calliphora vomitoria is the type species of the genus Calliphora. It is common throughout many continents including Europe, Americas, and Africa. They are fairly large flies, nearly twice the size of the housefly, with a metallic blue abdomen and long orange setae on the gena.
Forensic geology is the study of evidence relating to materials found in the Earth used to answer questions raised by the legal system.
Historic paint analysis, or architectural paint research, is the scientific analysis of a broad range of architectural finishes, and is primarily used to determine the color and behavior of surface finishes at any given point in time. This helps us to understand the building's structural history and how its appearance has changed over time.
Body identification is a subfield of forensic science that uses a variety of scientific and non-scientific methods to identify a body. Forensic purposes are served by rigorous scientific forensic identification techniques, but these are generally preceded by formal identification. This involves requesting a family member or friend of the victim to visually identify the body.
Alan Wayne Jones is a researcher and scholarly writer on the subject of forensic toxicology and human physiology relating to alcohol consumption. Jones was born in Pontypridd, Wales, UK, but worked for most of his career in Sweden.
Phadebas is a synthetic biochemical substrate used for both qualitative and quantitative assessment of the α-amylase enzyme. Its active component is DSM-P, microspheres in which a blue dye has been chemically bound. When the substrate is digested by the amylase enzyme in solution, it releases that blue dye at a rate proportional to the quantity of the enzyme present. It is used in a range of applications from quality control tests for food & beverages to detection of saliva stains in forensic investigations.
Wildlife forensic science is forensic science applied to legal issues involving wildlife. Wildlife forensic sciences also deal with conservation and identification of rare species and is a useful tool for non-invasive studies. Methods can be used to determine relatedness of the animals in the area allowing them to determine rare and endangered species that are candidates for genetic rescue. Techniques using things such as the SSCP or Single-Strand Conformational Polymorphism gel electrophoresis technique, microscopy, DNA barcoding, Mitochondrial Microsatellite Analysis and some DNA and Isotope analysis can identify species and individual animals in most cases if they have already been captured. Unlike human identification, animal identification requires determination of its family, genus, and species, and sex in order to individualize the animal, typically through the use of DNA based analyses.
Forensic geophysics is a branch of forensic science and is the study, the search, the localization and the mapping of buried objects or elements beneath the soil or the water, using geophysics tools for legal purposes. There are various geophysical techniques for forensic investigations in which the targets are buried and have different dimensions. Geophysical methods have the potential to aid the search and the recovery of these targets because they can non-destructively and rapidly investigate large areas where a suspect, illegal burial or, in general, a forensic target is hidden in the subsoil. When in the subsurface there is a contrast of physical properties between a target and the material in which it is buried, it is possible to individuate and define precisely the concealing place of the searched target. It is also possible to recognize evidences of human soil occupation or excavation, both recent and older. Forensic geophysics is an evolving technique that is gaining popularity and prestige in law enforcement.
Listed here are the human Y-chromosome DNA haplogroups found in various ethnic groups and populations from North Africa and the Sahel (Tuaregs).
Ear print analysis is used as a means of forensic identification intended as an identification tool similar to fingerprinting. An ear print is a two-dimensional reproduction of the parts of the outer ear that have touched a specific surface. Ear prints and their use for identification were first discovered by Fritz Hirschi in 1965. Fritz Hirschi was the first to identify a criminal using this method, in Switzerland in 1965 and ear print analysis has also been successfully used to solve crimes in the UK and the Netherlands. In addition to identification, the height of an ear imprint at a crime scene may also provide investigators with information regarding the stature of the perpetrator.
Human identification by forensic scientists can be done by three primary methods: friction ridge analysis, DNA analysis, and comparative dental analysis, the latter of which is one of the duties of a forensic odontologist. It is the process of identification by a post-mortem dental examination of a deceased individual ; comparing those findings with the ante-mortem dental records, radiographs, study casts, and so on believed to be those of the individual implicated; and assessing the concordance and/or discrepancy between the two. Teeth are resilient and—along with the highly specific and unique type, location, and configuration of restorations—might be the only features usable for the identification of bodies found in burnt, decomposed, skeletonised, or macerated condition.
Candice Mae Bridge is an American chemist and Associate Professor of Chemistry and Forensic Science at the University of Central Florida. Her research considers the development of mass spectroscopy for forensic analysis, including the characterization of lubricant from rape victims and residue from gunshots, as well as the identification of drugs in urine samples.