An erasure is a type of document alteration used by forgers to change the document’s meaning for any extraneous gains or profits. The forger erases any part of the document by any means. In this article, we’ll know the ways of creating erasures and the ways of its detection.
The erasures are primarily carried out chemically or mechanically, which can be detected by several techniques like oblique lighting, microscope, fuming method, heating of the document, ultraviolet rays, Infrared luminescence, etc. These techniques help us detect the erasures and easily read out the erased text of the altered document.
Along with the topics discussed above, we will also discuss the different ways of document alteration by a forger, such as obliterations, alteration by addition, alteration by substitution, and the ways to detect them.
Evaluation of Erasures
The standard way to alter any document is carried out by erasing a partial part of the document. The erasures of any document (typed, printed, written, etc.) are being carried out efficiently with the help of chemical or mechanical means. Certain chemicals like chlorine water, bromine water, and sulphuric acid remove or decolorize the writing on the document. Certain inks are soluble in solvents like alcohol, acetone, and water. Detergents can be used to remove specific ink, such as carbon ink.
An eraser, rubber, knife, blade, or sandpaper is used to remove the writing in a document by softly scratching the material on the document. While erasing the written text on the document, the upper fibers of the document will get disturbed and some particles of an eraser can be seen on the surface of the paper.
To detect or observe these changes, we generally examine the document under a microscope with the help of direct lighting or by allowing the light to strike the paper obliquely from either side of the document. We can observe the disturbing fibers of the paper due to eraser, blade, knife, sandpaper, etc.
When the chemicals are used for erasures, we can detect and restore the original writing with the help of the fuming method. Fuming of vapors of iodine, ammonium sulfate, alcohol, etc. the erased part of the document is recovered.
Sometimes carelessly, we wash our documents kept in our clothes pocket. Detergents and water are great solvents to remove the ink. However, we can recover the removed ink by the process of heating. We can keep the erased document in a heating chamber like an oven for some time at a specific temperature.
Ultraviolet and Infrared Luminescence Examination
The wavelength of the radiations lying in the regions of ultraviolet and infrared regions when striking the erased portion of the document helps detect the erasures’ sites and make the text visible. The incident light’s mechanism of absorption, transmission and emission (UV & IR) reveals the erased text.
Alteration by Addition and Substitution
The ordinary poor writing or the patching of the current writing of the document results in document alteration. It can be made even after erasures. The most common type of alterations is overwriting, changing of numerals, etc.
The simple alterations can be easily detected under a simple microscope. To detect the minute differences in the pen strokes of the document, we use a stereoscopic binocular microscope. Slight differences in the ink color and the writing style can also be detected by stereoscopic binocular microscope.
Obliteration means the effective destruction of the writing appearance without removing it or making it invisible. Overwriting with a pen or pencil or making the writing invisible by the use of fluid. We can decipher the obliterated writing by the following method:
- Examination of the document under intense light at different angles, especially with transmitted light.
- Examination under UV radiations.
- Examination using color filters.
- Examination using Visual Spectral Comparator, which can scan a document at different wavelengths of UV, IR, oblique lighting, transmitted light, etc. We can even compare the document writing by placing them side by side or one over the other.
- Laser sources are also used to detect obliteration, alteration, and ink comparison.