It is proven that two human beings are not likely to have the same fingerprints (even twins) and it is also suggested that an individual's fingerprint does not change throughout his/her lifetime (unless a significant injury scars the fingers)
Visible Prints
Also called patent prints. Usually left in some medium that reveals them to the naked eye. Formed when substances such as blood, dirt, ink or oils on the finger comes in contact with a smooth surface and leave an impression that is visible without development.
Impressed Prints
Also called plastic prints. Indentations left in soft pliable surfaces such as clay, wax, paint or other surface that will hold the impression. Visible and can be viewed or photographed without development.
Latent Prints
Usually not apparent to the naked eye. Form from sweat on the body or water, salt, amino acids and oils contained in sweat. Must be developed before they can be seen or photographed. Can be made visible by dusting, fuming or chemical reagents.
RIDGES AND PORES ACTIVITY
Wood Glue Method
So basically, we applied the glue onto a finger and waited for it to dry before peeling it off with a pair of forceps. We were then supposed to place it under microscope and examine the details of the fingerprint.
Aim: Capture ridge and pore details of your finger using a polymer cast.
Unfortunately, mine failed twice. D: The first time I tried, it wasn't really dry when I peeled it off so yeah it obviously didn't work out well. For the second time, mine kept folding up and eventually turned into a ball of crap. But I managed to take a look at Sheena's polymer cast (hers succeeded on her first attempt) and I guess the pores, which are on the skin, are rather regularly-spaced.
Cyanoacrylate (Superglue) Fuming Method
The basic concept of this method is to apply something that will chemically react with one or more of the constituent chemicals of latent fingerprints. The product of the chemical reaction will render the fingerprints visible. Superglues typically contain methylcyanoacrylate or ethylcyanoacrylate, which react with traces of amino acids, fatty acids and proteins in the latent fingerprint and the moisture in the air to produce a visible, sticky white substance along the ridges of the fingerprint. To enable such a reaction, cyanoacrylate must be in its gaseous form, so a fume box is used. Heat is then applied to allow superglue to vapourise.
Aim: To develop latent prints on a non-porous surface using superglue fuming method.
All our fingerprints weren't really visible though. But to enhance the fingerprint, I guess we can use the dusting method? :/ I'm not too sure though but it seems feasible. Might probably allow the fingerprint to be more visible so that a good, detailed photograph can be captured.
Iodine Fuming Method
Physical process. Natural body fats and oils in latent print temporarily absorb the iodine vapours, resulting in change in colour (colourless to brown). This temporary change fades with time as the iodine that is absorbed will eventually dissipate into the atmosphere.
Aim: To develop latent prints on a porous surface using Iodine Fuming Method.
The fingerprints were actually quite visible. (: But faded away after awhile. To render the prints more permanent, certain materials can be applied to allow the developed print to be photographed at the greatest intensity of colour change and then allowed to fade.
Powder Dusting Method
Finely-crushed powder is applied to a surface. Oils and perspiration form the common residue on fingers that get transferred when a print is made, allowing minute particles of powder cling to the latent residue, making it visible.
Aim: To develop latent prints using Power Dusting Method.
I attempted the Power Dusting Method twice. First attempt was rather unclear. Details (e.g. lines) were not really visible cos I didn't really brush the powder well. The second attempt was a little better I guess. Details are now a little more visible, but still not really good. :/ Magnetic powder can also be used, where a fine magnetic powder is held by a magnetic applicator, which may then be gently moved across the fingerprint. This is actually a more effective method, as no bristles touch the surface and is hence the print is less damaged.
Fingerprinting using inkpad!
-insert scanned picture here-
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