[Fig. 69]
[Fig. 70]
Figure 71 is an example of loops as they appear on the rolled impression portion of a fingerprint card.
[Fig. 71]
![[Enlarge]](#2873848932677661140_fig071a.jpg.id-6378717966788362027.wrap-0.html.html){kind=link}
Ridge counting
The number of ridges intervening between the delta and the core is known as the ridge count. The technical employees of the Federal Bureau of Investigation count each ridge which crosses or touches an imaginary line drawn from the delta to the core. Neither delta nor core is counted. A red line upon the reticule of the fingerprint glass is used to insure absolute accuracy. In the event there is a bifurcation of a ridge exactly at the point where the imaginary line would be drawn, two ridges are counted. Where the line crosses an island, both sides are counted. Fragments and dots are counted as ridges only if they appear to be as thick and heavy as the other ridges in the immediate pattern. Variations in inking and pressure must, of course, be considered.