Evaluating the effectiveness of optical techniques for establishing the sequence of inkjet printed text with writing pen ink lines

The present study aimed to determine the order of homogeneous and heterogeneous crossing strokes (color basis) of inkjet printer (red, blue and black) with gel pen and ballpoint pen ink lines (red, blue and black). The samples of crossing lines were examined under stereomicroscope and light emitting diode (LED) microscope and techniques were compared on the basis of their conclusions. The samples of crossing lines of gel pen and ballpoint pen inks of red, blue and black with inkjet printed text of red, blue and black were prepared on three different substrates that include A4 office paper, bond paper and stamp paper. It was noticed that once again stereomicroscope proved to be successful technique than the LED microscope in establishing the sequence of crossing lines of gel pen ink and ballpoint pen ink (red and blue) with inkjet printer ink lines of black colour on all three different substrates. Alternatively, LED microscope was unable to reveal the order of strokes of gel pen and ballpoint pen ink lines (red, blue and black) with inkjet printer ink lines of all colors. It is found that the vital role in observation under microscopes is played by the correct angle of light source. Therefore, it is suggested to forensic document examiners (FDE's) to prioritize the optical microscope having suitable light angle so that it can able to project the light at an appropriate angle onto the sample to examine the sequence of crossing strokes of inkjet printer with writing pen ink lines.