Fingerprint Talk.....Terms and Techniques: Fingerprints can be used for a number of various identification processes. They are used to identify victims of accidents, amnesia, or to verify records...but most importantly they are used to identify suspects in crimes. Fingerprints can give us hints as to a person's gender, size, and occupation A taller person might leave higher prints on a wall, a construction workers prints maby be show callouses and so on. Fingers are not the only source of reliable prints. Bare feet and the palms of our hands can also be sources of identifying prints. Prints develop while we are still in our mothers womb, click HERE to learn about the physical development of fingerprints. dactylography......is the study of fingerprints. basic ridge characteristics.....arches, loops and whorls. See chart above. Individuals of African ancestry tend to have plenty of arches, Europeans have frequent loops, and Asians/Orientals have a high frequency of whorls. In order for a fingerprint to match evidence in the U.S., it must have 12 common points of comparison. The FBI-NCIC classification system and other techniques known as the Henry Fraction assign numerical values to overall patterns on an entire set of fingerprints. This is why we are able to file millions of prints in an organized, orderly fashion. |
FINGERPRINTING |
What are fingerprints? We have all seen them, on windows, drinking glasses, and shiny surfaces. They are actually a result of the oils from glands in our skin which lie among folds and ridges. When pressed on a surface, the ridges deposit oil on the surface. The chart at left shows typical patterns these ridges make when pressed against a surface. |
Taking a closer look..... |
The History of Fingerprinting....Click on the print. |
Why Fingerprint? |
Fingerprints are an infallible means of personal identification. Each of us is unique not only in the development of our digital ridges during embryological development but also in the way our hands are affected by our environment and diseases. In history, early civilizations, criminals were often branded or maimed as a means of identifying the fact that the individual had committed a crime. The Romans relied on tattoos as a way to identify soldiers to prevent desertion of mercenaries. Alphonse Bertillon developed of systematic body measurements that could be used to specifically identify an individual since it appeared that all individuals had different measurements according to his calculations. But, in 1903 two men were found to have the same Bertillon dimensions and the practice was elimianted. Camera images change with age. DNA fingerprinting though very high tech is costly and time labor intensive. Finger prints do not change with age. They can be used to identify persons suffering with amnesia, victims of accidents, to verify records, and most importantly to link suspects to crimes. Fingerprints can provide us with hints as to a criminal's size, gender, and occupation. Palm prints, a bare foot, and a hand can also produce images that can be analyzed in the same way that a fingerprint can be analyzed. During fetal development the ridges form on the fingers and thumbs. These ridges arrange themselves in more or less regular patterns. Experts divide these patterns into three basics: ARCHES LOOPS WHORLS See the chart at the top of the page for examples of each. |
Dactylography....Fingerprinting! |
Each pring has its own unique combination of overall pattern and special ridge characteristics. No two prints have ever been found that were exactly alike. Even those of identical twins are different. In the U.S. for a print to be a match, there must be 12 common point of comparisons between the suspects and the evidence. The FBI-NCIC classification system and other techniques known as the Henry Fraction assign numerical values to overall patterns on an entire set of prints. This allows the coding and filing of millions of prints in an oderly manner. |
Fingerprint Talk.....Terms and Techniques: Fingerprints can be used for a number of various identification processes. They are used to identify victims of accidents, amnesia, or to verify records...but most importantly they are used to identify suspects in crimes. Fingerprints can give us hints as to a person's gender, size, and occupation A taller person might leave higher prints on a wall, a construction workers prints maby be show callouses and so on. Fingers are not the only source of reliable prints. Bare feet and the palms of our hands can also be sources of identifying prints. Prints develop while we are still in our mothers womb, click HERE to learn about the physical development of fingerprints. dactylography......is the study of fingerprints. basic ridge characteristics.....arches, loops and whorls. See chart above. Individuals of African ancestry tend to have plenty of arches, Europeans have frequent loops, and Asians/Orientals have a high frequency of whorls. In order for a fingerprint to match evidence in the U.S., it must have 12 common points of comparison. The FBI-NCIC classification system and other techniques known as the Henry Fraction assign numerical values to overall patterns on an entire set of fingerprints. This is why we are able to file millions of prints in an organized, orderly fashion. |
Plastic....type of print made as an impression in soft material such as clay, wax, paint, or putty. Visible...type of print left when blood, dirt, ink or grease come into contact with a smooth surface. Latent....prints which are normally invisible and must be developed before they can be seen or photographed. |
Common types of prints..... |
Collection of the fingerprint ..... |
Dusting for prints.... Because our fingers carry a coating of perspiration and oil, when a print is left, this sticky residue will collect powder when lightly dusted leaving a ridge impression. Ideal surfaces for dusting include polished wood, glass, metal, plastics, formica and tile. Still workable not as good are cardboard, paper, and leather. Powders vary in properties and colors. They may be fluorescent or magnetic. They come in a variety of colors including black, white, grey , aluminum, red and gold. Color is selected to provide the greatest contrast to the surface background. When the background surface is multicolored, for example a magazine page, it is best to use fluorescent and view with a UV light. For porous materials like leather, raw wood, paper and cardboard, it is best to use a cloud of finely suspended iron particles held in place by a magnetic wand. Ostrich feathers are often used when large surface areas need to be dusted. Lifting prints... Lifting a print involves using an adhesive to physically raise the print impression from the surface where the powder has been applied. It may be lifted with a hinged lifter, a rubber lifter or cellophane tape. Chemically lifting can be accomplished using fuming iodine (good for porous materials), NINHYDRIN spray ( good for wallpaper, books and developing prints up to 30 years old!) or silver nitrate (good for wood or cardboard). Check out the photograph of the bike above, it is being chemically dusted with superglue fuming. Superglue on a hotplate placed in a container with the object to be fingerprinted results in visible gray prints in 15-20 minutes. The most recent advance in this area of crime investigation has been the laser which is in essence the use of photoluminescence. |
They stand ready, they are our sons, our daughters, husbands, and wives....they are members of our armed forces around the world. This site is dedicated in their honor. |
