Abstract: Portable shadow moire apparatus is disclosed for indiscriminately manipulng the grid and light source thereof over a specimen surface, with the grid oriented substantially in parallel therewith and in close proximity thereto. Self aligning support is provided on such apparatus, along with height adjustability for that support. Utilization of very high density grids is made possible by such apparatus to enhance the detection sensitivity thereof. Light source direction variability is also provided to control the magnitude of detectable distortion.