At the point of intersection, correctable carbon ribbon strokes over ball-pen line appear as compact black layers, masking the ball-pen lines and interrupting the ...
Forensic Science International
Forensic Science International 64 (1994) 141-145
Determining the sequence of intersecting ball-pen lines and correctable carbon ribbon strokes Atul K. Singla”, Om Prakash
Jasuja*b,
Jaswinder
Kaurb
‘Forensic Science Consultant. Patiala. India hDeparfmenf of Forensic Science. Punjabi University. Patiala-147 002, India
(Received 24 March 1993; revision received 21 July 1993; accepted 2 August 1993)
Abstract The chronological sequence of intersecting ball-pen lines and type-written correctable carbon ribbon strokes can easily be determined on the basis of the difference in their relative gloss/sheen. At the point of intersection, correctable carbon ribbon strokes over ball-pen line appear as compact black layers, masking the ball-pen lines and interrupting the continuity of its sheen, whereas ball-pen lines over correctable carbon ribbon strokes show continuity in
the sheen of the line at the point of intersection. The results have been found to be highly reliable. Key words: Documents;
Sequence; Intersections;
Ball-pen lines; Correctable
carbon
ribbon
strokes
1. Introduction With the advent of electronic typewriters using correctable carbon ribbons, the forensic document examiner is faced with another problem of determining the sequence of intersecting correctable carbon ribbon strokes vis-a-vis other typing/ writing instruments in cases where there is a dispute regarding the chronological order of typewritten matter with respect to other writings/signature(s). A wealth of information is available in the scientific literature regarding the determination of the sequence of strokes/lines of conventional writing/typing instruments. Some workers have also suggested methods for determining the sequence of intersecting correctable * Corresponding author. 0379-0738/94/$06.00 0 1994 Elsevier Scientific Publishers Ireland Ltd. All rights reserved SSDI 0379-0738(93)01424-P
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carbon ribbon strokes and other writing instruments. Megevand et al. [1] have suggested a technique based on the removal of the typewritten portion from the intersection with the help of corrector ribbon and examining the residue of the formation remaining on the paper, and the examination of the transfer of ink onto the corrector tape. These workers have found their technique to be highly satisfactory but partially destructive. They have also specified the difficulty of lifting the portion of intersection,in cases where the paper surface is not highly sized and slightly shiny. Hart and Carney [2] have also suggested a somewhat similar technique based on the physical removal of the layer of carbon stroke from the point of intersection and lifting of the carbon stroke with the help of adhesive tape. These workers have worked on the assumption that in the area where the typing was done first, there should be an absence of ink, whereas the ink would be present under the carbon layer when the writing was done prior to the typing. They have also obtained good results in line intersection problems involving carbon typewriter ribbon and ball-point, roller-ball and fine-point tibre tip pens. It has, however, been noted that the technique is destructive in nature. Moreover, it is not always easy to lift the carbon strokes from the paper, as the ink of correctable ribbon begins to ‘set up’ on the paper after a certain period of time. Depending on the length of time, it becomes more and more difficult to remove it completely [3]. In the present paper, we suggest a totally non-destructive technique for determining the sequence of intersecting correctable carbon ribbon strokes and ball-pen lines. This technique is based on the simple phenomenon of the difference in the relative sheen/gloss of the correctable carbon ribbon strokes and ball-pen lines. The composition of correctable carbon ribbon strokes is such that under magnification they appear as compact black layers [4], whereas the ball-pen lines have a characteristic glossy appearance with pasty texture. Due to this difference in the relative sheen, ball-pen lines over correctable carbon ribbon strokes show continuity in the sheen of line at the intersecting point, whereas correctable carbon ribbon strokes over ballpen lines appear as compact black layers masking the ball-pen line and interrupting the continuity of its sheen at the point of intersection. The polishing of the typewritten stroke(s) by the rotating ball of the pen in ball-pen lines over typewritten strokes is another factor [S]. 2. Method The suggested technique is based on the simple examination of the intersection under a common stereomicroscope using a beam of incident light falling at about 45” on the surface of paper from an incandescent light source placed at a distance of - 5 or 6 in. The angle of incident light can, however, be adjusted with respect to the surface of paper and the direction of strokes to get best results. Under stereomicroscope, the correctable carbon ribbon strokes appear as compact black layers, whereas the ball-pen lines have a glossy appearance. From this difference in the relative gloss, the sequence of strokes can be determined with marked accuracy. When the ball-pen line is over the typewritten stroke, it shows continuity in the gloss, whereas when the typewritten stroke is over the ball-pen line, the gloss of the ballpen line at the point of intersection is masked by the typewritten stroke, and it shows breaks in the gloss.
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2.1. Trial Two hundred samples using different makes of electronic typewriters equipped with a daisy wheel (fitted with different brands of correctable carbon ribbons) and ball-pens (red, blue and black ball-pens of Indian as well as foreign origin) were prepared on Sunlit* and Executive* bond papers, and on rough types of papers with no sizing. The papers were placed on different types of writing surfaces such as glass and hard wood table tops, stacked papers and metal sheet, etc. (Since the strokes of correctable carbon ribbons basically appear as compact black layers showing no noticeable difference in optical examination [4] and the ball-pen lines have a glossy appearance, the makes of typewriters, ribbons and ball pens were not found to affect the results.) The sequences of different intersections were recorded on separate sheets and these were not known to the examiners. All three authors examined the samples independently under a stereomicroscope with an incandescent incident light beam falling at an angle of about 45” to the surface of paper from a distance of - 5 or 6 in. The samples were examined using different magnifications ranging from x 20 to x 50, and by adjusting the direction of strokes/lines with respect to the direction of incident light to get the best results. The observations made by the workers were then compared with the original sequence keys. On average 98% results were found to be correct. The sequence could not be determined in 18 cases where the typewritten strokes and/or the ball-pen lines were thin and light. The errors were found in the cases in which the workers tried to find the sequence when the strokes were thin and the intersections were not clear. It was comparatively easy to determine the sequence of red and blue ball-pen lines and carbon ribbon strokes as compared to the black ball-pen lines and carbon ribbon strokes. 3. Results and discussion After conducting trials we found that it is very easy to determine the sequence of intersecting ball-pen lines and typewritten correctable carbon ribbon strokes. The correctness of the results was 98%. The technique is completely non-destructive and the sequence can be photographically demonstrated. As is evident from Fig. lA, the typewritten strokes over the ball-pen lines have interrupted the continuity of the ballpen line at the intersecting points. The masking of the line is apparent from the breaks in the gloss of line at the intersecting points. In Fig. lB, the continuity of the ball-pen line indicates that it is over the typewritten strokes. We are of the opinion that more than one point of intersection should be examined before rendering a definite conclusion. It may not be possible to determine the sequence when the type faces have thin stroke widths and/or the ball-pen lines are thin or light. The time gap between the ball-pen line and the typewritten strokes, nature of the paper surface, nature of the writing support and the makes of ribbons and ball-pens have not been found to affect the results.
*Brand
names.
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Fig. 1 (a) Typewritten strokes over horizontal ball-pen line, masking the gloss of line at intersecting points (shown by arrows). (b) Ball pen line over typewritten strokes, showing continuity in its gloss.
4. Conclusions The research is encouraging and the results have been found to be highly reliable. With this optical technique, it would probably be possible to avoid destructive or partially destructive tests. The authors intend to carry on research and to find out non-destructive techniques for the determination of the sequence of correctable carbon ribbon strokes with respect to other writing instruments.
5. References 1
B.A. Megevand, P.A. Hurni, J.A. Toppolet and J. Mathyer. Determining the sequence of two intersecting lines, one of which has been typed with correctable carbon rihbon. Int. Grim. Police Rev., 401 (1986) 217-222.
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Linda J. Hart and Brian B. Carney, Typewriting versus Writing Instrument: A line intersection problem. J. Forensic Sci., 34 (1989) 1329-1335. M.A. Casey and D.J. Purtell, IBM correcting Selectric typewriter: An analysis of the use of correctable film ribbon in altering typewritten documents. J. Forensic Sci., 21 (1976) 208-212. J. Mathyer and R. Pfister, The examination of typewriter correctable carbon film ribbons. Forensic Sci. hf., 25 (1984) 71-80. Linton Godown, Sequence of Writings. J. Grim. Law, Criminal. Police Sci., 54 (1963) 1329-1335.
