I utilize a variety of laboratory instruments in my work. For example, a simple loupe (magnifier), is often used to enlarge fine details in writing or printed text. If further magnification is used, a microscope is very useful in examining printing processes, ink strokes, security features and other document features.
Obliterations or alterations often involve inks different from the original entries. A sophisticated instrument using infrared filters and ultraviolet light is used by forensic document examiners for such examinations. Foster and Freeman makes a Video Spectral Comparator (VSC), allowing ink comparisons and many other types of document analysis.
Ink dating is not a testing process common to most document examiners, particularly in private laboratories. The chemical analysis for ink dating is a very specialized field. If ink dating would be of benefit to a case, a document examiner will refer the client to an ink chemist.