Modern document examiners can detect alterations, erasures, and obliterations; resurrect evidence deteriorated by fading or decomposition; and recover entire documents, or portions of documents, from underlying pages, which were present when the original document was written. Document examiners use such equipment as the Video Spectral Comparator, Raman Spectral Comparator, and Electrostatic Detection Apparatus. When a subject makes an alteration on a document, a different pen is often used from the original writing. The Video Spectral Comparator uses filters to vary the light bombarding the document. Varying inks will fluoresce differently and reveal two writing samples made with two different pens at two different times. The Raman Spectral Comparator (RSC) is similar with two important differences. The RSC bombards the target with laser light instead of light waves. The RSC output is a graphical depiction of the exact chemical composition of the object targeted by the laser rather than a visual image. RSC analysis is applicable to inks, papers, and dyes. Electrostatic Detection Apparatus operates somewhat like a photocopier and is normally used to recover invisible indented writings. There are two other important types of evidence that can be developed from many documents: fingerprints and DNA. Fingerprints can be patent, such as visible greasy or bloody handprints, or latent, such as invisible prints left behind by the natural oils on fingerprint ridges. Forensic scientists now can obtain and analyze invisible microscopic samples of DNA. Many States now are moving toward DNA sample collection in all felony cases, in addition to sexual offenses and violent offenses.