This kind of fingerprint is the most common, making up 60 percent of fingerprints. The fingerprint ridges flow in on one side of the finger and flow back out the same side, forming a loop. This type is divided into radial loops and ulnar loops; of these two, ulnar loops are more common. Radial loops face towards the thumb, in the direction of the radius bone, while ulnar loops face towards the ulna, towards the little finger.
The whorl is the second most common type of fingerprint, making up 34 percent of fingerprints. They tend to have ridges that form circles. They are divided into the accidental whorl, central pocket loop whorl, plain whorl and double loop whorl. The accidental whorl makes up 1 percent of fingerprints.
This is the rarest out of the three types, making up 5 percent of fingerprints. The arch fingerprint is divided into the plain arch and the tented arch sub-types, and of these two, plain arches are more common. The plain arch ridge pattern involves the ridges flowing in from one side, rising upwards and going back down to flow out the other side to form a rounded peak. A tented arch has a group of ridges in the middle that form a peak that is less than 90 degrees.
In a crime scene, fingerprints are classified as to how they are made. These ways are visible, molded and latent. Fingerprints classified as visible are made with a substance that can be seen with the eye, like paint. Latent fingerprints are fingerprints that the eye cannot see, made with sweat and oil from the body. Plastic fingerprints, also known as molded fingerprints, are fingerprints made when a person's finger pressed into something soft like clay or soap.