Images

"An optical appearance or counterpart of an object, such as is produced by rays of light either reflected as from a mirror, refracted as through a lens, or falling on a surface after passing through a small aperture. Such an appearance may also be a mere subjective impression on the sense of sight, as an after-image, and the negative or accidental image seen after looking intently at a bright-coloured object, and having a colour complementary to that of the object. An image produced by reflexion or refraction is called in Optics a real image when the rays from each point of the object actually meet at a point, a virtual image when they diverge as if from a point beyond the reflecting or refracting body."