Each daguerreotype is a one of a kind and possesses an authority; most are delicate, defined, of substantive weight, small enough to be held in the hand, when angled change from positive to negative and “transcend reality: appear to float in space behind glass.” Given that they are created by the action of photons on solid silver, there is no visible grain, unlike modern film. In addition, one sees a mirror image on a mirror-like surface. In 1840, Alexander-Edmond Becquerel, who was one from a line of scientific family members, introduced the less dangerous process: a silver-coated daguerreotype plate fumed with iodine vapors and underexposed in a camera, developed/intensified by a secondary after-exposure under red glass, fixed, and washed. Commercial daguerreotype studios often placed a sitter in front of large windows to get maximum light.