For materials with refractive index greater than 2, the focus will be located inside the sphere. In this case the image is not directly accessible, while the closest accessible point is on its surface directly opposite the source of light. However, few materials have a refractive index this high. For a refractive index of 2, the image forms on the surface of the sphere, and the image may be viewed on an translucent object or diffusing coating on the imaging side of the sphere.