Delta
Definition
Triangular ridge formation at the point where parallel ridge flows diverge. Arches have 0 deltas, loops have 1, whorls have 2 or more.
- Field
- Fingerprint pattern classification
- Arch pattern
- 0 deltas
- Loop pattern
- 1 delta
- Whorl pattern
- 2 or more deltas
Common questions
Why is delta count used to sort fingerprint patterns?+
The number of deltas is a quick, reliable structural feature that separates the three broad pattern types before any detailed ridge comparison begins, making it a first-pass classification tool.
Is the delta the same feature examiners use for ridge counting?+
Yes, in loops and whorls the delta serves as one fixed reference point, paired with the core, from which examiners count intervening ridges for detailed pattern sub-classification.
Related terms
- ACE-V
- Analysis, Comparison, Evaluation, Verification: the four-stage method for latent print examination used by accredited forensic fingerprint laboratories. Analysis examines the latent in...
- Adermatoglyphia
- Rare genetic disorder, sometimes called immigration delay disease, in which a person is born without friction ridges. The standard counter-example to the...
- Core
- The approximate centre of a fingerprint pattern. In a loop, it is identified as the innermost recurving ridge's peak or the tip...
- Dermal Papillae
- Peg-like projections of the dermis into the epidermis. Their geometry sets the ridge pattern in stone before birth. Damage limited to the...
- Friction Ridge
- Raised epidermal ridge on the palmar surface of fingers, palms and soles, formed during foetal life from the underlying dermal papillae. The...
- Henry Classification
- Numeric filing system built at the Calcutta Fingerprint Bureau in 1897. Assigns a numerator and denominator from whorls on even and odd...
- Minutiae (Galton Points)
- Local ridge features used for individual identification. The classical set is ridge ending, bifurcation, dot, island or lake, bridge, hook or spur,...