Essentials Of A Loop



- A sufficient recurve.



- A delta.



- A ridge count across a looping ridge.



A sufficient recurve may be defined as that part of a recurving ridge

between the shoulders of a loop. It must be free of any appendages

abutting upon the outside of the recurve at a right angle.



Appendages--Some explanation is necessary of the importance attached

to appendages. Much care must be exercised in interpreting appendages

because they sometimes change the shape of the recurving ridge to

which they are connected. For example, a loop with an appendage

abutting upon its recurve between the shoulders and at right angles,

as in illustration 56, will appear sometimes as in illustration 57

with the recurve totally destroyed. For further examples see figures

161 to 184.







The same is true of a whorl recurve, as in figures 58 and 59.



It is necessary, therefore, to consider and classify figures 56 and 58

as if they actually appeared as in figures 57 and 59.



In figure 60, there is a ridge marked A which enters on one side of

the impression and, after recurving, passes an imaginary line drawn

from the core C to delta D, and terminates on the same side of the

impression from which it entered, marked B, thus fulfilling all the

conditions required in the definition of a loop. X and Y are the type

lines. It will be noted in figure 61 that there is a ridge which

enters on one side of the impression, recurves, and passes an

imaginary line drawn from the delta to the core. It does not terminate

on the side from which it entered but has a tendency to do so. In this

case, all the requirements of the loop have been met, and consequently

it is classified as such.











Figure 62 shows a ridge entering on one side of the impression,

recurving, and passing beyond an imaginary line drawn from the delta

to the core, although opposite from the pattern shown in figure 61.

After passing the imaginary line, the recurving ridge does not

terminate on the side of the impression from which it entered, but it

has a tendency to do so, and the pattern is, therefore, a loop.



In figure 63, a ridge enters on one side of the impression and then

recurves, containing two rods within it, each of which rises as high

as the shoulder of the loop. From our study of cores, we know that the

top of the rod more distant from the delta is the core, but the

recurving ridge does not pass the imaginary line. For that reason the

pattern is not classified as a loop, but is given the preferential

classification of a tented arch due to the lack of one of the loop

requisites. The proper location of the core and delta is of extreme

importance, for an error in the location of either might cause this

pattern to be classified as a loop.



Figure 64 reflects a similar condition.



















In figure 65, there is a looping ridge A which enters on one side of

the impression. The ridges B and C are the type lines. As determined

by rules already stated, the location of the core and the location of

the delta are shown, and if an imaginary line were placed on the core

and delta, the recurving ridge A would cross it. This is another

figure showing a ridge which does not terminate on the side of the

impression from which it entered but tends to do so, and, therefore,

is considered as a loop.



In figure 66, we have a print which is similar in many respects to the

one described in the preceding paragraph, but here the recurving ridge

A continues and tends to terminate on the opposite side of the

impression from which it entered. For this reason the pattern is not a

loop, but a tented arch. The recurving ridge must touch or pass the

imaginary line between delta and core and at least tend to pass out

toward the side from which it entered, so that a ridge count of at

least one can be obtained.







Figure 67 shows a ridge which enters on one side of the impression

and, after flowing toward the center, turns or loops on itself and

terminates on the same side from whence it entered. This pattern would

be classified as a loop. This pattern should be distinguished from the

pattern appearing in figure 139. Careful study of the pattern in

figure 67 reveals that the core is located at C and the delta D. The

imaginary line between these points will be crossed by the ridge

forming a loop. In figure 139, the core is located on the recurve and

an imaginary line between the delta and the core does not cross a

looping ridge. Figure 139 is thus classified as a tented arch, as will

be seen later.



Figure 68 shows at the center of the print a ridge which forms a

pocket. It will be noticed that ridge A does not begin on the edge of

the print, but this is of no significance. The ridge A within the

pattern area recurves or loops, passing the imaginary line between the

delta and the core, and tends to terminate toward the same side of the

impression from whence it entered. This is a loop pattern possessing

all of the requirements.



In figures 69 and 70, it will be observed that there is a ridge

entering on one side of the pattern which recurves and then turns back

on itself. These patterns are different from any others which have

been shown in this respect but are classified as loops. In each of the

patterns the core and delta are marked C and D. The reader should

trace the type lines in order to ascertain why the delta is located at

point D, and then apply the delta rule.









Figure 71 is an example of loops as they appear on the rolled

impression portion of a fingerprint card.









Right Hand

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1. Thumb 2. Index 3. Middle 4. Ring 5. Little

finger finger finger finger

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Left Hand

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6. Thumb 7. Index 8. Middle 9. Ring 10. Little

finger finger finger finger

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