Obverse-Reverse Intersection of Lines
The dating of entries in two-sided medical records and diaries throughmicroscopic
examination of obverse-reverse intersecting lines.
This is an extension of a technique first reported to my knowledge by
PaulOsborn. The procedure can only be used where a questioned entry appears
ona document that contains entries on both sides, and is of particular
valuein the examination of medical records or diaries. Commonly, an entry
thatcontains exculpatory information will appear on one side of this page.
Ifa line from this entry intersects with writing on the back, many times
itcan be determined which was written first.
The procedure is in theory quite simple. As all document examiners knowwhen
one writes on a piece of paper an impression is created on the writingsurface
and a corresponding raised portion (convexity) occurs on thereverse side.
The depth of the impression and the height of the resultingconvexity on
the reverse side are of course controlled by the pressure,instrument,
paper and writing surface. When a convexity of sufficientheight occurs
it will appear as a ridge when viewed through a steroscopicmicroscope
using oblique light. The original inked line where itintersects this ridge
will cause a break in this ridge, if the inked linewas created second.
If the inked line was created first and the convexitysecond, the inked
line will appear to ride up over the convexity withsharply defined sides
signifying that the inked line was on the paper whenthe writing on the
reverse side was done causing the convexity and pushingthe inked line
up and away from the paper.
Pressure variation of the writer exhibits such a strong influence that
inone intersection the evidence may be insufficient to arrive at a conclusionbecause
the intersection may occur at a light upstroke while at anotherintersection
the pressure may be heavier and present clear evidence of thewriting sequence.
Typical uses of the procedure would be the examination of the diary pagesthat
are two sided and medical records that contain entries from differenttimes
and/or dates on both sides. For example, entries commonly appear indoctors'
progress notes that reference a patient's refusal of a diagnosticprocedure.
The entry is for purposes of this paper dated 06/12/89 andintersects with
another entry on the reverse side dated 02/06/91. Thisexamination procedure
can clearly demonstrate whether the patient refusedportion of the 06/12/89
entry was written before or after the 02/06/91entry was on the paper.
An examination of the inks with an image converter most of the timediscloses
the patient refusal language to be a different ink than used forthe corpus
of that day's entry, albeit perfectly color matched. The doctorwill then
state that he must have picked a different pen from his pocketwhen he
made that entry, but he made it that day, 06/12/89. The questionthen becomes
when was this entry written. The evidence contained inobverse-reverse
intersecting lines can answer that question withspecificityand at times
date entries within hours if the intersecting lines are thesame day but
different times.
References: The Sequence of Ballpoint Ink Strokes and Intersection Embossings,
PaulOsborn, American Society of Questioned Document Examiners, 1966Conference:
New York City, New York.
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