| dc.description.abstract | Charred documents pose a significant challenge in forensic document examination,
requiring specialized techniques for their stabilization and decipherment. Conventional
methods for charred document examination commonly employ chemicals such as
polyvinyl acetate (PVA) for their preservation; however, the use of PVA and similar
chemicals presents several drawbacks, including limited availability, toxic effects, non-
biodegradability, poor resistance to weather and moisture, and slow setting speed. These
limitations highlight the need for alternative, more environment-friendly solutions that can
effectively stabilize and preserve charred documents while facilitating their future
examination and analysis. This thesis aimed to address this need by proposing a green and
novel coating material synthesized from natural polysaccharides, providing a promisin
g alternative to polyvinyl acetate to stabilize and decipher charred documents.
Exploration of natural products to synthesize coating materials involves mucilage-rich
resources like fenugreek seed mucilage, okra mucilage, sago, and tamarind seed powder,
but optimum results couldn’t be obtained in terms of consistency, transparency, and
smoothness. Further investigation disclosed pure starch as a great resource to synthesize
the analog, which has proven to be an exceptionally good material for stabilizing and
preserving charred documents. Furthermore, once applied to the charred documents, the
synthesized analog also makes the invisible writing visible, which was an extra advantage
of the synthesized product.
Synthesis of starch analog involved the microwave irradiation of an optimized amount of
starch, glycerol, in the presence of acetic acid to get requisite consistency and
transparency. Starch, concentration, reaction duration, and temperature of the reactions
were the other parameters that were needed to regulate to get the best optimum results.
Out of varied concentrations, the best result was achieved with 6% starch solution
microwaved at 80 oC for 12 minutes. In addition, the characterization of starch and its
analog using ATR-FTIR spectroscopy for spectral determination and MALDI-TOF mass
spectrometry for mass analysis revealed the formation of a functional peak of ether-linkage
in the starch-based analog, which was further confirmed by its mass, i.e., n[C35H64O27]
+
at
916.36 corresponds to the molecular mass of the synthesized starch-based analog.
[viii]
Moreover, the coating of charred documents with synthesized analog involved varied types
of charred documents, which vary considerably depending on the types of paper, the type
and colour of ink used to make a document, and the temperature. Some other
environmental factors also play an important role in charring that affects the nature of
charred documents. Different paper and ink reach their maximum charring stage before
their carbonized ash stage at different temperatures. In this study, documents were made
using 18 different ballpoint and gel pen inks of different brands and colours on 3 types of
paper viz., 75 gsm JK copier, 90 gsm bond excel paper, and 100 gsm diary paper. The
combinations made on 75 gsm copier paper got maximum charred at 300 oC, while the 90
gsm and 100 gsm were at 304 oC and 308 oC, respectively.
The fragile charred documents were then stabilized and preserved using the starch-based
analog, and the result showed that, once the documents were coated with analog, the
coating dried within 10-15 mins, and the documents gained an appreciable strength. Hence,
the analog’s coating aided in the preservation of fragile and brittle masses of charred
documents, which can now be easily handled and used for further investigation.
Additionally, results of deciphering the content on charred documents using starch-based
analog showed that the documents made with ballpoint pens, particularly black and red
ballpoint inks of Linc Pentonic and Hauser Germany, gave the best results of decipherment
by producing contrast and revealing the invisible texts. The G-lens also recognized
successfully 100% deciphered characters in combinations from 17 to 21, i.e., BLBP Hauser
Germany on 90 gsm and 100 gsm; RBP Linc Pentonic on 75 gsm, 90 gsm, and 100 gsm
paper; and in combination-25 and 27, i.e., RBP Hauser on 75 gsm and 100 gsm. Moreover,
the red ballpoint pen ink of Linc Pentonic manufacturer, irrespective of type and thickness
of paper, showed the highest rate of success in decipherment, resulting in 100% correct
character recognition using G-lens unlike the document samples containing gel pen inks.
On the other hand, some combinations were not deciphered at all, and the texts were not
visible to the naked eye. For example, the blue ballpoint of the Unique EZY manufacturer
showed 0% character recognition through G-lens; however, a few characters were very
faintly visible to the naked eye that the G-lens could not recognized. In addition, the blue
gel inks of Elkos Magic manufacturer also gave 0% character recognition via G-lens. The
least significant result was shown by the red gel pen inks of all three manufacturers used in
the study i.e., RG Classmate Octane, RG Elkos Velo, and RG Reynolds Jiffy on all three
[ix]
types of paper i.e., 75 gsm copier, 90 gsm bond paper, and 100 gsm diary paper. This can
be due to the ink formulation of red gel ink, which is a water-based solvent in gel form.
Furthermore, the colour of the dyes present in the red gel ink affects the decipherment of
the texts on different paper substrates. The red gel ink residue may not produce contrast
after getting adhered to the starch-based analog applied on the charred documents due to
their colour behaviour. Besides this, the majority of the combinations of pen and paper
gave promising results of more than 70% character recognition, which can provide a
sufficient hint and clarity to the questioned document examiner while deciphering the
content of the document linked to any offence. This presented the great success and
efficiency of a novel synthesized starch-based analog in stabilizing the charred masses of
documents that either accidentally or deliberately underwent fire incidents and turns into
black, carbonized, fragile, and brittle states that need processing for bringing back their
original content without much compromising with their loss.
Moreover, the stabilized charred documents were further visualized under a more
sophisticated instrument VSC, widely employed in forensic science laboratories for
document examination. By this technique, it was observed that when the documents were
viewed under VSC, even after a month of stabilization and decipherment at different light
sources like, a flood light, white spot, and side light at different longpass (wavelength) like
VIS, 645, 695, 715, 725 and 850, proved to provide sufficient character decipherment in
the majority of combinations, while in the red gel pen inks, the decipherment was not
found appreciable. This is because every ink has a different wavelength and thus absorbs
light under visualization at different intensities. However, the VSC provided a sufficient
clue in the document combinations with no-to-little decipherment of texts.
After the stabilization and decipherment, the documents were tested for increased strength
after coating and preserving the charred documents using a Bursting Strength tester. The
analysis showed that there was a significant increase in the bursting strength of stabilized
and coated charred documents with that of non-coated. For example, the combination of
Linc Pentonic blue ballpoint pen ink on 75 gsm paper had a bursting strength of 0.12
kg/cm2
, which, after getting stabilized, gained an adequate increase in strength to 0.21
kg/cm
2
. Similarly, the bursting strength of combination BBP Linc Pentonic on 90 gsm
bond paper charred at 304 oC had risen in strength from 0.15 kg/cm2
to 0.25 kg/cm2
. These
findings demonstrate that applying starch-based analog over the charred documents made
[x]
with different pen and paper combinations strengthened the charred paper surfaces by
absorbing and penetrating the layers of charred masses, thus providing a better stabilization
and preservation technique.
In conclusion, the study on deciphering charred documents using ballpoint and gel pen inks
of different colours and brands on various paper grades has yielded significant findings.
The utilization of a starch-based analog, G-lens, and Video Spectral Comparator has
demonstrated promising potential in enhancing the visibility and recovery of ink residues
on charred surfaces. While black and red ballpoint pen inks displayed a higher success rate
in decipherment, other ink types and colours, such as red gel, presented greater challenges
due to variations in ink composition and colour intensity. The success of this integrated
approach highlights the importance of employing multiple techniques to overcome the
complexities associated with charred document analysis. Furthermore, findings
demonstrate the effectiveness of this technique in uncovering hidden text and shedding
light on critical details that were once lost to fire damage. This breakthrough holds
significant implications for forensic investigations, offering a promising avenue for
recovering and analyzing vital information from charred documents using commonly
available materials. Future research endeavours should focus on further refining and
expanding the application of these methodologies, thereby advancing our capabilities in
forensic investigations and contributing to elucidating critical information hidden within
charred documents. | en_US |
