Rub a small area of a piece of paper gently with a pencil, holding the tip of the pencil on its side. Once the paper is covered with a layer of graphite from the pencil, take a friend's finger and roll the tip of his finger gently over the paper. The finger from tip to just below the first joint should be covered in a layer of graphite.
Gently press the finger onto a piece of transparent sticky tape. Stick the tape onto a piece of clean paper to act as a fingerprint card, labeling each card with the finger number and hand as you go. Repeat for all 10 fingers.
Take a single separate fingerprint of the index finger of the person you are testing. This will act as your sample. Take one fingerprint from the index finger on your own hand. This will help show you differences and similarities in the prints.
Use a magnifying glass to compare each test fingerprint with the fingerprints of your friend. First look at the loops, whorls and arches. A whorl looks like a whirlpool, with concentric ridges surrounding each other. An arch looks like a hillside because the ridges rise up in the middle to form a hill shape. A loop is an area where the ridges rise up, but they rise steeply and the inside ridges are as steep as the outside ridges.These three major fingerprint patterns are not specific enough to match fingerprints by, but they are useful for excluding many non-matching prints.
Use the magnifying glass to identify smaller parts of each pattern known as minutiae. Each fingerprint can have up to 100 minutiae that you can use as comparison points.
Draw outlines of the fingerprint samples you have taken. Draw the whorls, loops and arches, making the outlines as large as possible. Look for ridge endings (where the ridge stops) first.
Compare all of the other minutiae points one by one. A ridge ending is where a ridge stops. A dot is a small ridge that looks like a dot. A hook is a short ridge that comes out of another ridge but has a free end. A bifurcation occurs when a ridge splits in two. An island is a short ridge between two longer ridges. A lake occurs when one ridge turns into a circle and then back into a ridge.
Continue your examination, remembering that fingerprints have complex organization and minutiae can be very complicated. A bridge is when a ridge splits off from another ridge and ends in a neighboring ridge. A double bifurcation is a ridge with two extra ridges forking off. A trifurcation looks like a fork but with three branches. An opposed bifurcation looks like two forks attached to each other by the handle. A ridge crossing is similar to an opposed bifurcation, but the handle ends are not present. Finally, an opposed bifurcation/ridge ending is a fork with a free end inside two ridges that are farther apart than usual.
Allocate a fingerprint outline to each possible matching print and compare each matching print to its outline one at a time. Mark points that correspond on the sample print and its possible match with a red marker. Mark points that do not correspond with a green marker.