Whether it is a signature on a check, a handwritten codicil to a will, an anonymous letter, or other document in which the authorship of the handwriting or signature is questioned or contested — the handwriting may be analyzed and compared to a known sample (exemplar) to make a determination as to authorship or authenticity.
Paper and ink are both three-dimensional media. Any attempts at alteration of handwriting or signatures, though carefully disguised, must physically disrupt the paper, the original ink, as well as the relationship of ink to paper. Such alteration may be detected through microscopic examination in conjunction with task-specific lighting, analysis and imaging techniques...
For additional information, and some guidelines respecting the examination and analysis of questioned handwriting and signatures, please visit our website -- www.HawkeyeStudios.com -- and click on Grapho-Lab Services.