A comparison microscope, or microscope comparator, is a vital tool in forensic science, particularly for ballistics. Initially developed by Philip O. Greville, it was Calvin Goddard who refined and popularized it.

Comparison Microscope, also known as Forensic Microscope. It is an important instrument mainly used in forensic labs, security printing works, banks, industry quality control dept., for comparison investigation of bullets & cartridges case, tool marks, currency, coins, banknotes, documents, stamps, seals, fingerprint, fiber, and more small evidence.