Instron (Norwood, Mass.) has developed the Hand-Operated Marker (HOM), a device designed for use with Instron’s noncontact video extensometers. The HOM allows for marks to be placed on a specimen with consistent size, color density and spacing. Inks subsequently will stretch along with the specimen, unlike traditional stick-on paper dots that may move as the material is being strained, which can introduce error. The manufacturer says well-defined dots on specimens improve the video extensometer’s dot-tracking algorithm performance and tolerance for other video image error sources, such as background color and density variations.