Common Terms
The Scientific Working Group on Friction Ridge Analysis, Study and Technology (SWGFAST) maintains a list of terms generally used and accepted within the fingerprint analysis community. Additional terms can be found on the SWGFAST website .
Arch, plain - A type of print pattern in which the friction ridges enter on one side of the print and flow out the other side with a rise or wave in the center.
Arch, tented - A type of print pattern similar to the plain arch but that possesses an angle, upthrust (central rise), or two of the three basic characteristics of the loop.
Cyanoacrylate - The primary (>98%) component of super glue; it is used in a fuming technique to develop latent (invisible) prints on a variety of surfaces so they can be photographed.
Core - A structure in the print that is the center line or lines of the print; it is important for conducting ridge counts.
Delta - A point in loop and whorl prints that lies within an often triangular, three-pronged or funnel-shaped structure; it is the part of a ridge nearest the point where two parallel ridge lines (the “type” lines) diverge to flow around the loop or whorl; loop patterns have one delta, which is the starting point for conducting a ridge count, and whorls have two or more, which are important for determining the whorl type.
Friction ridge - The raised portion of the skin of the print, consisting of one or more connected ridges.
Furrow - A valley or depression between friction ridges.
Loop - A type of print pattern in which one or more friction ridges enter on one side of the print, curve up and around and back down, then flow out on the same side of the print from which it entered; types can be divided into left slant loops and right slant loops or, if the source of the print is known to be a specific hand (the left or right), into radial loops (the pattern flows in the direction of the radius bone of the forearm, toward the thumb) and ulnar loops (the pattern flows in the direction of the ulna bone of the forearm, toward the little finger).
Loupe - A small, often frame-mounted magnifier used for examining fingerprint detail.
Print - The mark made by a finger or thumb on a surface or in a soft material such as wax or wet paint; can be patent (surface-visible), latent (surface-invisible), or plastic (3-dimensional in soft material).
Ridge counter - A handheld, pointed tool used for counting the number of ridges during fingerprint analysis.
Shoulder - The point of a loop’s recurving ridge where it curves back around.
Whorl, accidental - A type of print pattern consisting of the combination of two different types of patterns (excluding the plain arch) with two or more deltas; or a print pattern type that possesses some of the requirements for two or more different types of patterns; or a print pattern type that conforms to none of the definitions of a pattern.
Whorl, central pocket loop - A type of print pattern that has two deltas and at least one friction ridge that makes one complete circuit, which may be spiral, oval, circular, or any variant of a circle; an imaginary line drawn between the two deltas does not touch or cross the “central pocket” (the recurving ridges within the inner pattern area).
Whorl, double loop - A type of print pattern that consists of two separate loop formations with two separate and distinct sets of shoulders and two deltas.
Whorl, plain - A type of print pattern that consists of one or more friction ridges making a complete circuit and two deltas; an imaginary line drawn between the two deltas touches or crosses at least one recurving ridge within the inner pattern area.