General Terms on Fingerprint Visualization
Absorption |
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A process through which material gets incorporated into another material, often the solid surface of a porous material.
Adsorption |
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A process through which material sticks or adheres to a solid surface of another material and resides as a film.
Alternate Light Source (ALS, a.k.a. crime scene lights)
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Light sources used during crime scene investigations that can enhance the visualization of many forms of evidence, such as fingerprints, to assist with identification. An example of a commonly used ALS is a black light (ultraviolet) flashlight.
Amino Acids
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The basic building blocks of proteins, which are used to make tissues in our body. Amino acids can be secreted from eccrine glands as sweat and deposited on various substrates.
Chemical Enhancement
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A chemical technique used to enhance an impression in order to increase contrast between the deposited fingerprint and its substrate.
Eccrine Glands
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Present all over the body but are the only glands present in volar skin. Sweat pores along the fingerprint ridges secrete eccrine sweat from these glands.
Eccrine Sweat
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This sweat is the main component of fingerprints that are left behind on surfaces from contact, and consists of amino acids, proteins, ions, electrolytes, and water.
Enhancement |
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Techniques used to improve the visibility of impressions
Fingerprint impression/mark
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Describes the transfer of oils or lipids from a finger onto a surface resulting in the replication of the friction ridge pattern seen on the fingertip, including the minutiae.
Friction Ridge (Fingerprint ridge)
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A raised texture on the palmar and plantar surfaces of primates that enhances their ability to grip objects.
Latent Impressions
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Marks or indentations left at a crime scene often in the form of handprints, footprints, or fingerprints that are not visible to the naked eye without some form of enhancement.
Lipids |
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These are fatty, oily compounds that are secreted from sebaceous glands as sebum and can be present in fingerprint impressions due to hand contact with other areas of the body (e.g., face, head).
Matrix |
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The chemical composition of a fingerprint impression. Often assumed to be a natural eccrine sweat or sebaceous sweat impression, but can also commonly be blood. Often there are contaminants such as hand lotion, dirt, or food residue, or job-specific contaminants such as paint, engine oil, etc.
Minutiae |
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Individualistic details of various levels observed within a fingerprint that are used to characterize a fingerprint in question. These details can be used for inclusion and exclusion purposes.
Non-porous surface |
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The surface of a substrate that prevents the absorption of a material into the substrate, causing materials to mainly deposit on top of the surface and adhere through adsorption (e.g., plastic, metal, some tapes).
Palmar and Plantar Surfaces |
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The palmar surface refers to the skin on the underside of the hand and the plantar surface refers to the soles of the feet. These surfaces do not contain sebaceous glands, only eccrine glands.
Porous surface |
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The surface of a material that allows for the absorption of the materials into the substrate (e.g., paper, leather, tape, clothing).
Reactive Substances |
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Some of the components of eccrine sweat and sebaceous sweat can be either chemically or physically enhanced through techniques to make latent fingerprint impressions more visible. These are mainly amino acids from the eccrine sweat and lipids from the sebaceous sweat.
Residue |
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Materials left on a substrate through contact, such as reactive substances.
Sebaceous glands |
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Small, oil-producing glands present in the skin that are associated with hair follicle presence, which produce and release an oily residue (lipid) called sebum. Sebaceous glands are not present on the plantar and palmar surfaces, but since the hands touch different regions of the body, sebum can often be picked up and deposited long with eccrine sweat, as part of the matrix of fingerprint impressions.
Sebaceous Sweat |
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Produced by sebaceous glands, this sweat is often found in fingerprints along with eccrine sweat. This sweat consists of oily residues (lipids) called sebum and is transferred to palmar surfaces from touching areas of the body that secrete sebaceous oils, such as the face.
Semi-porous surface |
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A surface of a material that has some properties of both non-porous surfaces and porous surfaces (e.g., some plastics, some tapes, glossy paper, etc.). Enhancement techniques specific to both porous or non-porous items may work on items that are semi-porous. They have varying degrees and combinations of absorption or adsorption of fingerprint impressions.
Substrate |
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The material upon which a fingerprint impression is deposited through contact. Substrates are often classified as porous, non-porous or semi-porous.
Volar skin |
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The textured skin located on the fingertips of primates. This skin provides a biological advantage to allow for the ability to hold onto things and have traction. Present on the palmar and plantar surfaces.
The surface of a material that allows for the absorption of the materials into the substrate (e.g., paper, leather, tape, clothing).
Friction ridge pattern that is found on the fingertips' skin.
Present all over the body but are the only glands present in volar skin. Sweat pores along the fingerprint ridges secrete eccrine sweat from these glands.
Describes the transfer of oils or lipids from a finger onto a surface resulting in the replication of the friction ridge pattern seen on the fingertip, including the minutiae.
The material upon which a fingerprint impression is deposited through contact. Substrates are often classified as porous, non-porous, or semi-porous.
The textured skin located on the palmar and plantar surfaces of primates. This skin provides a biological advantage to allow for the ability to hold onto things and have traction.
A small orifice at the surface of the skin, through which gases, liquids, and small particles can pass. Characteristics of the pore that are measured include shape, size, and density.
This sweat is the main component of fingerprints that are left behind on surfaces from contact, and consists of amino acids, proteins, ions, electrolytes, and water.
Individualistic details of various levels that are observed within a fingerprint. These details are used to characterize the fingerprint in question and for inclusion and exclusion purposes.
Small oil-producing glands present in the skin that are associated with hair follicle presence and release/produce oily material called sebum. Sebaceous glands are not present on the plantar and palmar surfaces but since the hands touch different regions of the body, they pick up sebum and deposit it, along with eccrine sweat, as components of fingerprints.
This sweat is found in fingerprints along with eccrine sweat. This sweat consists of oily residues (lipids) called sebum and is transferred to finger and palm surfaces from touching areas of the body that secrete sebaceous oils such as the face.
A determination made by the examiner that there is sufficient agreement between the friction ridge patterns of a known and unknown fingerprint to conclude that both fingerprints may have originated from the same source.
A determination made by the examiner that there is sufficient reliable detail of characteristics in disagreement, such that one can conclude that two fingerprints (friction ridge impressions) did not originate from the same source.
A process through which material gets incorporated into another material, often the solid surface of a porous material.
A process through which material sticks or adheres to a solid surface of another material and resides as a film.
A chemical technique used to enhance an impression in order to increase contrast between the deposited fingerprint and its substrate.
The basic building blocks of proteins, which are used to make tissues in our body. Amino acids can be secreted from eccrine glands as sweat and deposited on various substrates.
These are fatty, oily compounds that are secreted from sebaceous glands as sebum and can be present in fingerprint impressions due to hand contact with other areas of the body (e.g., face, head).
Some of the components of eccrine sweat and sebaceous sweat can be either chemically or physically enhanced through techniques to make latent fingerprint impressions more visible. These are mainly amino acids from the eccrine sweat and lipids from the sebaceous sweat.
The plantar surface refers to the soles of the feet. This surface contains only eccrine glands and not sebaceous glands.
The palmar surface refers to the underside of the hand, including fingers. This surface contains only eccrine glands and not sebaceous glands.
The surface of a substrate that prevents the absorption of a material into the substrate, causing materials to mainly deposit on top of the surface and adhere through adsorption (e.g., plastic, metal, some tapes).
A surface of a material that has some properties of both non-porous surfaces and porous surfaces (e.g., some plastics, some tapes, glossy paper, etc.). Enhancement techniques specific to both porous or non-porous items may work on items that are semi-porous. They have varying degrees and combinations of absorption or adsorption of fingerprint impressions.