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Forum URL: http://www.webbsleuths.com/cgi-bin/dcf/dcboard.cgi
Forum Name: more and more JBR
Topic ID: 1942
Message ID: 6
#6, RE: OEJ
Posted by DonBradley on Feb-11-04 at 12:03 PM
In response to message #5
>Typically, two sets of photographs are taken at a crime
>scene: one with a scale; the other without.
>
>This is so the no one can say any evidence was hidden by the
>ruler.
The ruler, or celluoid scale, that is often used has a technical name that escapes me at the moment. It is more than just a metric scale used to indicate size. The shaded circles at each end with their crosshairs allow precise determination of camera angle and so precise measurement of the object, since an oblique angle of the camera would give a distored view of the ruler and therefore a possibility of a distorted measurement of the object being photographed. It is really a forensic tool to not only allow measurement of the object but to provide proof that the object was indeed photographed in a correct manner. The second photo is usually taken first, so that there is proof that nothing was obscured or altered by placing the metric scale down. If you are photographing a blood spot. You take the photgraph first, then you place the celluloid scale device and take the photgraph again. Often those yellow plastic with black numerals are placed close together and photos are sometimes taken first to make sure nothing was missed or obliterated by placing the yellow evidence signs.