Although there are a lot of rules that come into play with regards to technical definitions of each type of pattern this is the basic rule towards each type of pattern. Learning classification and all the rules that apply takes some time, like about 40 hours, but this will give you a pretty good grasp of what each pattern is and why it is such a pattern. The first thing that you need to understand is what a delta is. A delta, by the technical definition is a place where two lines run side-by-side and then diverge with a significant pattern area in front of the divergence. In a little more plain english it means that a triangle is formed. In Image 1 at right you can see where the three sides of the delta are formed by the lines in red. Look at this carefully and make sure that you understand what constitutes a delta. It is very important that you understand what a delta is because all of the pattern definitions require that you understand and be able to identify the delta or delta's or the lack of one. Remember to be a valid delta you should be able to see where three lines form three sides of a triangle.
Okay with that understanding here is what defines a particular pattern: If the print has one delta then the pattern is a loop. If the pattern has more than 1 delta then it is a whorl and if it has no delta's then it is an arch. Simple enough so long as you can effectively identify the delta's. In Image 2 at left you can see where the delta's are identified by the red box's in the image. This print has two delta's and therefore it is a whorl. Incidently, contrary to some police shows, there is no such thing as a "sworl" although some people seem to think so. There are 4 pattern types to whorls. The one shown in Image #2 is a plain whorl. Whorl pattern types include plain, central pocket, double and accidental. In addition to the pattern type of a whorl the tracing is also an issue when making a classification of a whorl pattern.
Finally we come to the last pattern type which is an arch. There are two types of arches, tented and plain but for now we will simply consider the concept of what an arch is. An arch is a pattern which has no delta. In Image 3 at right you can see an example of this. You can plainly see (hopefully) that there is no delta. The lines of this pattern tend to come in one side of the print and exit the other side without much of a change in the pattern. Arches are not that common and are probably the easiest pattern to recognize except for some of the tented arches which may, at least at first glance, appear to be a small count loop. All of the requirements and further examples of each pattern type and the rules associated with that particular type are explained in much greater detail on other pages. |
