a substantially isotropic illumination source utilizes a generally spherical , translucent diffuser . the spherical diffuser has an inner wall and a diffusive outer wall . light is communicated inwardly to the sphere along a first hemisphere . light is diffused and homogenized by internal reflection within the sphere and communicated outwardly through a complimentary hemisphere . this light , upon being diffused by the external or outer wall is substantially isotropic . the isotropic light so generated is utilized for video inspection of translucent specimens with improved contrast to facilitate detection of flaws therein . another aspect utilizes a specimen itself as the isotropic diffuser .