Forensic Science, 8 (1976) 165 - 173 0 Elsevier Sequoia S.A., Lausanne -- Printed in the Netherlands

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DETERMINATION OF THE SEQUENCE OF WRITING ON BOTH SIDES OF A PAPER

ANTONIO I. CAPON1

Sucre 2112, 1428 Buenos Aires (Argentina)

(Received November 24,1975; accepted June 28,1976)

SUMMARY

One of the most difficult subjects the Examiner of Questioned Documents has to deal with is the determination of the sequence of written materials. As far as this author knows, techniques are available only for cases where the relevant writings are placed on the same side of the paper.

Numerous experiments have been made on a range of papers varying in weight. In all of these tests both sides of the paper were typewritten as well as handwritten (pencil, pen, ball-point pen and fountain pen). Several samples are shown where the possibility of such determination is seen to be feasible, especially in cases where both sides are type- written and where one is typewritten and the other is handwritten with pencil, ball-point pen and fountain pen.

One of the most difficult problems the Examiner of Questioned Docu- ments has to deal with is perhaps the determination of the sequence of 2 writings.

The bulk of information I have at hand shows that so far the available techniques employed to solve this kind of problems are useful only when the 2 samples are written on the same side of a sheet.

For a long time I have considered the feasibility of determining the se- quence of writings even when they are written on opposite sides of the same sheet of paper. In order to obtain a response to that question I began to experiment with a wide range of papers of different weights, by writing with different elements, as well as typing with varied degrees of force settings.

In order to get as many intersections of different writing elements as possible, 2 sets of each paper were used as follows: The front side, which bears the brand name, was divided horizontally into 6 sections of approxi- mately 1.5 cm, identified by the letters a, b, c, d, e and f (cf. Fig. A). In these sections, the following writing elements were used:

a - light pencil b - heavy pencil c - light ball-point pen d - heavy ball-point pen e - light fountain pen (Pelikan) f - heavy fountain pen (Pelikan)

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1 r

I /

i ; !__Ll-

2 3 4 5 Fig. A. Sectioning of front side of test sheet of set 1 and reverse side of set 2.

Fig. B. Sectioning of reverse side of test sheet of set 1 and front side of set 2.

On the other side, 7 vertical divisons labelled 1 to 7 were drawn (cf. Fig. B), which were typewritten as follows:

1 - standard manual machine (black cotton ribbon) 2 - standard manual machine (red cotton ribbon) 3 - electric IBM Executive, impression indication set at 5 4 _ I, rr I, I, II rr ” 10 5 _ I, rr I, II I, I, ” 15 6 - electric IBM Executive, impression indicator set at 20 7 _ I, II ,I I, I, I, ” 25 In cases 3 to 7 a polyethylene ribbon was used. On the second sheet, the inverse procedure was used: the typing was on

the front and the handwriting on the back following the same distribution as explained above.

In the 2 sets the front side of the paper was written first. Following this procedure, it is possible to find points of intersection bet-

ween each of the handwritten and typewritten sections. In this way, one can see for instance the intersections of strokes of a light pencil with a manual machine, as well as with an electric one in 5 different degrees of pressure. The same holds true for strokes of heavy pencil, light ball-point pen, heavy ball-point pen, light fountain pen and heavy fountain pen.

Illuminating with a strong sidelight, a Leitz microscope was used to observe all the available intersections on those papers. Some interesting clues that might prove useful in order to reach a correct conclusion about similar sequences were found.

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In order to show the nature of these findings, photomicrographs of differ- ent intersections were taken. Results are presented below as paired photo- graphs, where the left picture shows the case when the handwriting was written first and the right one the case when the typed material was made first. In that way, side by side comparison of those pictures clearly shows the difference in both situations (Figs. l-24).

Tests have also been made by typewriting on both sides with IBM Execu- tive and IBM 72, 82 and 82 C machines (Selectric, Selectric II and Selectric Correcting type in the U.S. market), following the same procedure explained above.

Fig. 1 and 4. Light ball-point pen and IBM Executive machine (impression indicator set at 20) on 82 g paper. Left (Fig. 1): on the center and on the upper left corner the typing makes the intersected embossed handwriting strokes rise up. Right (Fig. 4): observe on the right the accumulation of ink over an embossed typed point.

Figs. 2 and 5. Heavy ball-point pen and IBM Executive machine (impression indicator set at 25) on 82 g paper. Left (Fig. 2): The point, comas, etc., typed on the back, clearly make the strokes previously handwritten on the front rise. Right (Fig. 5): There is accumulation of ink over the already typed signs.

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Figs. 3 and 6. Light fountain pen and IBM Executive machine (impression indicator set at 20) on 82 g paper. Phenomena similar to those described in the previous sets can be clearly observed here.

Figs. 7 and 9. Heavy pencil and heavy typewriting (IBM Executive, impression indicator set at 20) on 90 g paper. In this case, not much difference was detected between the 2 samples.

In this type of machines the point, comma, semicolon, dash, slash, diacrit- ical points and other signs, emboss the paper deeper than the other characters. (capital and lower letters). While in the Executive model the typebars can be individually balanced in order to get an even writing, to my knowledge, in the other models all the characters should strike alike according to the degree previously selected.

The deeper impression of the signs mentioned above in the case of the Selectric machines obey the fact that the mechanical impulse is the same for any of the symbols over the writing element. The subsequent deformation on the paper’s surface is proportional to the applied pressure, i.e., striking force of the element divided by the sign’s contact section of the paper. Thus,

Figs. 8 and 10. Heavy ball-point pen (upper section) and light fountain pen (lower section) and IBM Executive (impression indicator set at 15) on 90 g paper. Observe in the middle of Fig. 10 how the ball-point pen stains some fibers of paper of an embossed point. This does not occur in the Fig. 8 where the ink stroke bends over the mound of a similar sign.

Figs. 11 and 13. Heavy ball-point pen and IBM Executive machine (impression indicator set at 15) on 94 g paper. Here the situation stated for Figs. 8 and 10 can also be seen: in Fig. 13 the stain of ink left by the side (rather than by the tip) of the ball-point on the embossing of a point can be noticed.

Figs. 12 and 14. Heavy fountain pen and IBM Executive machine (impression indicator set at 15) on 94 g paper. Similar observations as those for Figs. 8 and 10 are applicable here.

Figs. 15 and 16. Heavy fountain pen and IBM Executive machine (impression indicator set at 25) on 106 g paper. The embossing of the typewritten signs on Fig. 15 can be seen clearly, while in Fig. 16 some of them appear flattened by the handwriting pressure.

Figs. 17 and 18. Light fountain pen and IBM Executive machine (impression indicator set at 20) on 118 g paper. Observations here are similar to those made for Figs. 8 and 10.

Figs. 19 and 21. Light ball-point pen and IBM Executive machine (impressionindicator set at 20) on 70 g paper. Notice in Fig. 21 the stain of the ink over the embossing of a point near the handwritten stroke, which is lacking in Fig. 19.

Figs. 20 and 22. Heavy fo luntain pen and IBM Executive ma set at 25) on 70 g paper. The same circumstances referred present in this particular ca se.

chine (impression indicator to Figs. 8 and 10 are also

Figs. 23 and 24. Light fountain pen and IBM Executive machine (impression indicator set at 20) on 40 g paper. In this case, the paper is so thin that the typewriting points are able to pierce it. However, when the handwriting is applied first (Fig. 23), the cut edge holes look neat: they are not stained by the ink. The inverse situation is seen in Fig. 24.

the point, being the sign with smallest contact section, is the one that deforms the paper the most.

Several examples are shown in Figs. 25-30. Figs 25 and 26 were obtained with an IBM Executive machine with the impression indicator set at 10. The rest of the Figures correspond to samples written using an IBM 82 C.

The examples shown above demonstrate the feasibility of determining the sequence of written material distributed over both sides of the same sheet of paper.

The above findings are based upon the physical fact that any writing material leaves either a mark or a groove on the paper’s surface. If the groove

Fig. 25. IBM Executive machine (impression indicator set at 10) on 70 g paper. One typed point flattens out a section of the embossing of a question sign. Compare this with the other question sign.

Fig. 26. IBM Executive machine (impression indicator set at 10) on 70 g paper. It can be seen how the slash almost splits the embossing of a previously typed point; also observe how the points typed at both sides of the former remain neat and their embossings are normal.

Fig. 27. IBM 82 C (impression indicator set at 2) on 94 g paper. A section of the number ‘9’ did not print just in the area occupied on the other side by a previous stroke.

Fig. 28. IBM 82 C (impression indicator set at 5) on 106 g paper. The left side of the base of an ‘1’ partially flattens out a point typed on the front of the paper.

is deep enough a complementary embossing appears the other side of the sheet. Needless to say, the deepness of the groove and the consequent embossing depend both on the pressure exerted to write and on the thickness and the quality of the paper employed.

The typewriting machines (specially the modern electric ones), strike the paper more deeply than the average handwriting. For this reason, in analysis of this kind, it is advisable to observe the document from the side opposite to the typewritten material to reach a conclusion.

The writing sequence between handwriting and typewriting is determined by the following method.

(a) If the document was typed first and the handwriting with ball-point pen or fountain pen made afterwards, probably some accumulation of ink

Fig. 29. IBM 82 C (impression indicator set at 5) on 106 g paper. The same occurs with the point of the question mark at the right over another point struck on the other side in first term.

Fig. 30. IBM 82 C (impression indicator set at 5) on 70 g paper. The right side of an ‘a’ deforms the embossing on a point typed before on the other side.

(or ink stains) are seen in the intersections between the strokes and the embossing. Moreover, when a heavy pressure is exerted by the writer, the embossing of the typewritten strokes tend to appear as being flattened out.

(b) On the other hand, if the typewritten material has been written in a second term, the crossed handwritten strokes will appear - even the pencil ones - as being raised from the paper: and neither stains nor ink accumula- tion are visible out of the borders of the pen strokes.

When the problem deals with typewritten material only, it is obvious that it is immaterial which side of the paper is examined. The sequence is deter- mined mainly investigating the embossing rather than the stroke itself. Thus, when in an intersection the embossing is flattened out, there is no doubt that the phenomena was produced by a subsequent typing on the other side of the paper.

Another clue to determining the sequence when both electric machines (especially Selectric) and polyethylene ribbon are employed, is the lack of printing when a character strikes over a previous stroke on the other side, as can be observed in Fig. 27.

However, some of the combinations of writing elements and pressures exerted require careful analysis and further research.