A properly equipped laboratory will have a a variety of instruments to use during examinations. One that is particularly useful, is the Video Spectral Comparator (VSC), that allows an examiner to compare inks. The VSC relies mainly upon the use of the infrared light spectrum, but has several other useful features. Although inks may visually appear the same to the human eye, differences are often vividly seen when the inks are subjected to the near infrared portion of light waves. The VSC is commonly used to examine alleged alterations of dollar amounts, ledger entries, medical records, etc. It may also be very useful resolving obliteration problems; the over-writing of text or numerals.
Instrumentation
