Fingerprinting

Answers to questions:

Ridges and Pores Activity:

Q. Where are the pores found? Are they regularly spaced?

A. They are found on the ridges of our fingers. Yes, they are, but may sometimes be erratically or randomly positioned.

Q. Are the lines of your print equally spaced throughout?

A. Mostly, but there are places where the lines merge, changing the distance between the lines. At other places the lines may not be curved in the same way as the rest, bending a different direction and thus causing the distance between the lines to change.

Cyanocrylate (Superglue) Fuming Method:

Q. If the contrast of the white print against the background is still too faint for a good photograph to be captured, what could be done to enhance the fingerprint?

A.

1. A greater amount or greater concentration of superglue could be used

2. The finger used to create the print could be made more oily first to enable a more distinct and clear print to be made

Iodine Fuming Method:

Q. What are the possible substances that may be used to render the prints more permanent?

A. The material used for printing the fingerprint on probably affects the time the print stays on it. To make the prints more permanent, they can be treated with a starch solution. Iodine and starch combine to form a deep blue-black complex, which persists for weeks to months, depending on storage conditions. Benzoflavone can also be used to treat prints to render them permanent.

Q. Why does the print disappear?

A. The natural body fats and oils in the latent print only temporarily absorb the iodine vapours when placed in the environmet containing the vapours (i.e. the gas jar), once removed from that particular environment, the vapours eventually dissipate back into the atmosphere and thus fade.

Powder Dusting Method:

Q. What is magnetic powder dusting and how does it work?

A. A magnetic applicator is used to attract magnetic powder, which is then lightly dusted over the fingerprint. It is usually used on non-magnetic, shiny surfaces such as plastic containers.

My own Fingerprint Database: Observations

1. Compare the fingerprint patterns on your right and left hand. Are they mirror images of each other?

My right and left thumbs can be considered mirror images of each other. However, the other fingers are definitely not mirror images of each other.

2. What kind of patterns do you see?

There are loops and whorls, but no arches.

3. Do the loops curve in the same or different directions in different fingers?

They are different for different fingers because no two prints are the same. One interesting thing observed is that most prints made by the left hand curve to the left and those on the right curve to the right.

4. Compare the size of the patterns e.g. How many ridges make up a loop?

Some fingers have more ridges making up the loop while others have fewer and thus smaller loops. They are not the same.