This slide is basically a conclusive result of various Research journals based on different disappearing ink's Examination and Analysis. The presentation comprises of research papers from Journal of Forensic science mainly from edition 1st - 8th. Hope this slide will be helpful for you all. Please have a look Gracias !

1. Examination of Disappearing Ink Writings
SUBMITTED BY:
Parth Chauhan
BSc. (H) Forensic Science VI Sem
A51605917024

2. Secret writing is the art of covered or hidden writing. The art of secret writing is intended
to make a message unreadable by at third party but does not hide the existence of the secret
communication. A new technique for committing document frauds using disappearing inks
in the execution of various bank instruments is currently very much in vogue. This study
deals with basic understanding about disappearing ink, different types of disappearing
inks, its compositions, laboratory preparation using different concentrations of chemical
compounds, comparative analysis between disappearing and erasable ink, Thermal ink as
disappearing ink, analysis fading time of different disappearing ink and decipherment of
the faded writing using physical and chemical methods and its consequence on the
evidences.
ABSTRACT

3.  Secret Writing: Secret writing is any means of written communication whereby a spy conceals the
actual written text, whether it is enciphered or encoded or not. Dissapearing inks are used for
secret writing.
 Disappearing ink: Inks that are visible for a period of time without the intention of being made
visible again are called disappearing inks.
 Many criminals defraud banks with untrue identification, falsified, fabricated or altered cheques,
bank instruments, other documents and stolen financial information.
 Criminals are using different types of erasures and disappearing inks to decolorize the writing for
fraudulent purposes.
INTRODUCTION

4.  The alteration is one of the most common types of fraudulent observed in the
examination of questioned documents. It includes addition, subtraction, and obliteration
and to alter any security features on the documents(4)
 Invisible inks can be classified into three main categories:
1. those that are revealed by heat,
2. those revealed by chemical reactions and
3. those that are visible under ultraviolet light.
 It is very difficult for bank officials to detect such types of bank instruments written with
disappearing ink, as there are no signs of either physical or chemical erasure in the
aforesaid instruments and hence forgers typically achieve success in their goals. This
laboratory dealt with a case of this very nature involving a bank cheque and, prima facie,
it was difficult to detect any alteration or tampering in the said cheque. (3)

5.  With the advancement of new research and technology, different types of pen having disappearing
inks are easily available in the market which are used by criminals for forgery.(2)
 Literature survey revealed that mainly two types of inks are used in such pens-
(i) Thymolphthalein and Phenolphthalein based disappearing inks or its mixture,
(ii)Inks based on thermochromic substances disappearing due to changes in temperature (thermal
erasable ink).(2)
 Some of the disappearing inks are water-based acid-base indicators (pH indicators), which change
from a coloured to a colourless solution upon exposure to air. The most common pH indicator for inks
is thymolphthalein (blue). This indicator is mixed with a basic solution that becomes more acidic
upon exposure to air, resulting in a change of colour.(5)

6. Principle of common disappearing inks

8.  We prepare ink using Thymolphthalein and Phenolphthalein separately.
 0.1 – 1.5 gm of Thymolphthalein or Phenolphthalein is dissolved in 60 mL of absolute ethyl
alcohol (laboratory grade) and solution is shaken until complete solubility.
 After then, 6 mL of Glycerin (laboratory grade) added in the solution and shaken and 34 mL
water to make 100 mL volume of each ink solution.
 0.5 – 4 mL of Sodium Hydroxide is then mixed keeping in mind the pH of the solution.
 Desired ink is prepared which can be used by filling it in appropriate writing instrument.
Preparation of common disappearing inks(1)

9.  Mohamed El-Molla Et. Al. in their research based on the experiment of different concentrations of
Thymolphthalein and Phenolphthalein ink and their mixtures on different types of papers were used
as described :
RESULT AND DISCUSSION
Papers Manufacturing company
White paper (80 g ⁄m²) Azhar (Al Husein International
Paper Industry, Giza, Egypt)
White paper (80 g ⁄m²) Xerox (Giza, Egypt)
White paper (80 g ⁄m²) Quena Paper Industry Company
(Kous, Quena, Egypt)
Edfo lined paper (60g ⁄m²) Edfu Misr Company
(Edfu, Asawan, Egypt)
Stencil printing paper (70
g ⁄m²)
Rakta Paper Manufacturing
Company (Abukeer Aalexandria,
Egypt)
PHENOLPHTHALEIN
in 60 mL Ethanol
THYMOLPHTHALEI
N in 60 mL Ethanol
0.1 gm(P1) 0.1 gm(T1)
0.2 gm(P2) 0.2 gm(T2)
0.4 gm(P3) 0.4 gm(T3)
0.8 gm(P4) 0.8 gm(T4)
1.2 gm(P5) 1.2 gm(T5)

10. Table 1: Effects of different conc. Of NaOH with different conc. Of Thymolphthalein on the fading time.
*Table 1 taken from El-Molla, M. M., Shama, S. A., & El-Sayed Saeed, S. (2012). Preparation of Disappearing Inks and Studying the
Fading Time on Different Paper Surfaces. Journal of Forensic Sciences, 58(1), 188–194*

11. Table 2: Effect of increase in volume of 1N NaOH with different conc. Of Thymolphthalein
Table 3 Effect of increase in volume of 1N NaOH with different conc. Of Thymolphthalein
*Table 2 & 3 taken from El-Molla, M. M., Shama, S. A., & El-Sayed Saeed, S. (2012). Preparation of Disappearing Inks and Studying the
Fading Time on Different Paper Surfaces. Journal of Forensic Sciences, 58(1), 188–194*

12. Table 4: Effects of different conc. Of NaOH with different conc. Of Thymolphthalein on the fading time.
*Table 4 taken from El-Molla, M. M., Shama, S. A., & El-Sayed Saeed, S. (2012). Preparation of Disappearing Inks and Studying the
Fading Time on Different Paper Surfaces. Journal of Forensic Sciences, 58(1), 188–194*

13. (1)Azhar x1000 (2)Xerox (x1000) (3)EDFO (x1000)
(4)Quena (x1000) (5)Rakta (x1000)
*Figure 1, 2, 3, 4 & 5 taken from El-Molla, M. M., Shama, S. A., & El-Sayed Saeed, S. (2012). Preparation of Disappearing Inks and Studying the Fading
Time on Different Paper Surfaces. Journal of Forensic Sciences, 58(1), 188–194*

14.  The stability of the handwriting increased with increasing the concentration of NaOH with the
same surface, and low concentration of NaOH resulted in colorless writing. Also, the stability of
the handwriting increased with increasing the concentration of Thymolphthalein and
Phenolphthalein.
 Azhar paper surfaces gave the more handwriting stability than Xerox, Quena, Edfo, and Rakta,
respectively.
 At high volumes of 1 N NaOH with phenolphthalein, the stability of handwriting decreased as a
result of the formation of the colorless carbinol form.(Fig. F)
Fig. 6: Carbinol form mechanism

15.  Later in 2012, Bikram Ashok Kumar Et. Al. in their research based on the experiment on
Thymolphthalein ink writings on different sample of cheques under VSC 2000.
Fig. 7. a) Photograph of a sample exhibit prepared using disappearing ink pen; b) photograph of secret writings
revealed below existing writings under a spotlight, a facility available in the VSC-2000 HR.
*Figure 7 (a) & (b) taken from Bikram Ashok Vaid, Sanjeev Kumar, Rajender Singh Rana, Narendra Kumar (2012).
Visualisation of disappearing ink writings. Problems of Forensic Sciences 2012, vol. 92, 311–318*

16. Fig. 8. a) Photograph of a bank instrument with existing writings submitted to this laboratory for verification of its authenticity; b)
photograph of secret writings revealed below existing writings under a spotlight, a facility available in the VSC-2000 HR.
Fig. 9 . a) Photograph of a bank instrument with existing writings submitted to this laboratory for verification of its authenticity; b)
photographs of secret writings revealed below the existing writings under a spotlight, a facility available in the VSC2000.

17. J(a) J(b)
J(c)
Fig 10. (a) Photograph of a bank instrument with existing writings submitted to this laboratory for verification of its authenticity;
b) photograph of secret writings revealed below existing writings under a spotlight, a facility available in the VSC-2000 ;
c) photographs of aforesaid instruments seen under transmitted light.

18. 11(b)
Fig 11. (a)Actual photographs of a bank instrument with writings and signatures executed with normal ink visible to the naked
eye; b) processed photographs of the same bank instrument as shown in Figure 11(a) above, revealing secret writings below the
existing writings using a spotlight in the VSC-2000 .
11(a)

20.  In 2013, Deepti Andharmule Et. Al. in their research based on the study of biological fluids(milk, saliva, and urine),
chemical fluids (vinegar, saline and baking soda) and vegetable fluids (lemon, orange and onion juice) and then
visualization by physical, chemical and by heat treatment with in the time interval of 30 days.
Table 5,6 & 7: Biological fluids, Vegetable fluids & chemical fluids visualized by physical
and chemical methods.

21.  In 2017, Hussain SS and Sahu M. in their research based on the study of biological fluids(Milk, Saliva, and Sweat),
chemical fluids (Detergent, Sugar solution and Vinegar) and Fruit juices (Lemon, Apple and Grape juice) and then
visualization by physical and chemical treatment with in the time interval of 30 days.
Table 8,9 & 10 : Fruit juices, Chemical fluids & Biological fluids visualized by physical
and chemical methods.

22.  In 2015, Vivek kumar Mangilal Chayal Et. Al. in their research based on decipherment of thermal ink on different
cheque papers.
Fig 12 (a) Sample of thermal ink in blue ink color; b) Photograph of the sample after applying heat on specific areas, original writings
disappeared and not visible; C) Sample of ghost strokes of disappeared writing of thermochromic thermal ink visible under UV 312 nm.
Fig.12(a) Fig.12(b)
Fig.12(c)

23. Fig 12 (d) Sample of rewritten/altered sample in blue thermochromic thermal ink; e) Ghost strokes of original disappeared
writing in altered/overwritten cheque visible under UV range 312 nm) in VSC-6000; f) Ghost strokes of original
disappeared writing in altered/overwritten cheque visible under UV range 365 nm in VSC-6000
Fig.12(d) Fig.12(e)
Fig.12(f)

24. Fig 12 (f) Ghost strokes of original disappeared writing and over written/altered writings visible under spot light in VSC-
6000; g) Reappeared original writing and over written/altered writing visible with the naked eye after cooling the sample
in a refrigerator at 0° to −10 °C.
Fig.12(f) Fig.12(g)
 Refrigerator based method is destructive technique in nature as the samples will get exposed to humidity
and moisture inside the chamber.
 The detection under VSC-6000 given better, result in terms of clarity compared to cooling and retrieving
under the freezing temperature in a refrigerator.

25.  In 2017, examination conducted on thermal ink (Frixion ink) by Chee Hau Teo Et. Al. in Malaysia using
ESDA and VSC 6000: used three color of thermal ink – Blue, Black & Red
1. All three inks gave consistent result after heated and erased as fading could be observed by magnifying
glass but reading is not possible that indictaed presence of ink after fading.
2. Due to writing, indentation can be found which can be restored using ESDA and oblique light using VSC.
3. The rubbing action by eraser against the paper shows Pilling effect of paper which can be observed using
oblique light examination in VSC as shown in fig.13(a).
Fig 13 (a) Black Frixion ink removed by heating, then analyzed using ESDA; b) Blue Frixion ink after erasure showing
visible indentation and pilling on the surface of paper.
13(a) 13(b)

26.  Thermal ink is the most commonly used ink among disappearing inks. The used is basically by cloth weavers
in factories and may be used in illegal way for committing property related crimes.
 Available non- distructive methods for examination includes VSC and ESDA. VSC can be used with UV and
spotlight.
 Available destructive method for examination includes Sodium hydroxide and ammonia solution.
 Best method for the detection of thermal ink writings is Iodine fuming as it will not harm the paper and writing
and evaporated after some time.
 VSC is much better technique for decipherment of thermal ink as compared to refrigeration technique which
may affects evidential value.
CONCLUSION

27. 1. El-Molla, M. M., Shama, S. A., & El-Sayed Saeed, S. (2012). Preparation of Disappearing
Inks and Studying the Fading Time on Different Paper Surfaces. Journal of Forensic Sciences,
58(1), 188–194.
2. Chayal, V. M., Handa, D. R., Singh, J., & Menon, S. K. (2015). “A Sensitive Non-destructive
Method for Detection of Document Frauds using Thermal Ink.” Australian Journal of Forensic
Sciences, 48(5), 601–612.
3. Welch, J. (2008). Erasable ink; something old, something new. Science & Justice, 48(4), 187–
191.
4. Deshpande Hemantini, Mulani Khudbudin(2018). Decipherment of disappearing ink: A case
study, Brazilian Journal of Forensic Sciences, Medical Law and Bioethics 7(3):156-161
REFERENCES

28. 5. Bikram Ashok Vaid, Sanjeev Kumar, Rajender Singh Rana, Narendra Kumar (2012).
Visualisation of disappearing ink writings. Problems of Forensic Sciences 2012, vol. 92, 311–318
6. Deepti Andharmule, Neeti Kapoor, Ashish Badiye (2013). An Evaluation of Some commonly
used Methods for Visualization of Secret Writing. Research Journal of Forensic Sciences, Vol. 1(3),
2321–1792
7. Manal Abd-El, Aziz Abd-El Zaher (2014). Different types of inks having certain medicolegal
importance: Deciphering the faded and physically erased handwriting. Egyptian Journal of
Forensic Sciences (2014) vol. 4, 39–44
8. Asicioglu, F., Tekin, T., Ozbek, N., Cevik, F. E., Ozcan, M., & Mohammed, L. A.
(2019). Prepared Disappearing Ink and Deciphering of Documents. Journal of Forensic Sciences.
9. Hussain SS, Sahu M (2017). A Study on Common Visualization Methods for Secret Writing done
by Invisible Inks and their Sensitivity Over a Period of Time. Austin J Forensic Sci Criminol. 2017;
4(2): 1061
10. Teo, C. H., Mohamad Noor, S. N. M., & Wong, K. Y. (2017). Ink that disappears: examination
of questioned documents related to Frixion ink in Malaysia. Canadian Society of Forensic Science
Journal, 50(3), 146–155.

29. THANKYOU