Ninety writers provided 10 genuine signatures, 5 disguised signatures, and 5 auto-simulated signatures. All 1800 signatures were collected using a digitizing tablet resulting in a database of each signature's dynamic characteristics. With genuine signatures, there were significant differences between styles for size, velocity, and pen pressure, and there were significant differences between genuine signatures and at least one of the un-natural signature conditions for all parameters. For velocity and size, these changes with condition were dependent on style. Changes with condition for the other parameters were similar for the three styles. This study shows that there are differences among natural signature styles and disguise behaviors that may be relevant in forensic signature examinations. (Published Abstract)