The red-eye effect in photography is the common appearance of red pupils in color photographs of eyes. Photography (fә'tɒgrәfi or fә'tɑːgrәfi (from Greek φωτο and γραφία is the process and Art of recording pictures by means of capturing Red is any of a number of similar Colors evoked by light consisting predominantly of the longest wavelengths of Light discernible by the human eye in the wavelength The pupil is the hole that is located in the center of the iris of the eye and that controls the amount of light that enters the Eye. A photograph (often shortened to photo) is an Image created by Light falling on a light-sensitive surface usually Photographic film or an electronic Eyes are organs that detect Light, and send signals along the Optic nerve to the visual areas of the brain It occurs when using a photographic flash very close to the camera lens (as with most compact cameras), in ambient low light. A flash is a device used in Photography that produces an instantaneous flash of artificial Light A point-and-shoot camera, also called a compact camera, is a Still camera designed primarily for simple operation Red-eye effect appears in the eyes of humans and animals that have no tapetum lucidum, hence no eyeshine, and rarely in animals that have a tapetum lucidum. The tapetum lucidum ( Latin: "bright tapestry" plural tapeta lucida) is a layer of tissue in the Eye of many Vertebrate animals that The tapetum lucidum ( Latin: "bright tapestry" plural tapeta lucida) is a layer of tissue in the Eye of many Vertebrate animals that The red-eye effect is a photographic effect, not seen in nature.
Because the light of the flash occurs too fast for the pupil to close, much of the very bright light from the flash passes into the eye through the pupil, reflects off the fundus at the back of the eyeball (see diagram in Eye), and out through the pupil. Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 The pupil is the hole that is located in the center of the iris of the eye and that controls the amount of light that enters the Eye. The fundus of the Eye is the interior surface of the eye opposite the lens, and includes the Retina, Optic disc, Macula and Eyes are organs that detect Light, and send signals along the Optic nerve to the visual areas of the brain The camera records this reflected light. The fact that the reflected light is red often is attributed to the ample blood supply of the retina and/or chorium, but this is incorrect. The red-eye effect is due to the color of the fundus, which is due to melanin, a pigment, principally located in the retinal pigment epithelium (RPE). Melanin is a class of compounds found in the Plant, Animal and Protista kingdoms, where it serves predominantly as a Pigment. In Biology, a pigment or biochrome is any material resulting in Color of plant or animal cells which The retinal pigment epithelium ( RPE) is the Pigmented cell layer just outside the neurosensory Retina that nourishes retinal visual cells and is firmly
Although in many animals the RPE is black, in humans it is brown. Red-eye effect is more pronounced in people and animals with grey or blue eyes, and in children. Eye color is a Polygenic trait and is determined by the amount and type of Pigments in the Eye 's iris. In both groups, all tissues of the eye have relatively less melanin. In a pale eye, and in a child's eye, not only does the iris have less melanin to stop stray light from passing through it, but also the retina and choroid have less melanin to absorb stray light that enters the eye. The vertebrate retina is a light sensitive part inside the inner layer of the Eye. The choroid, also known as the choroidea or choroid coat, is the vascular layer of the Eye lying between the Retina and the Sclera The role of melanin in red-eye effect is most clearly seen in animals with heterochromia: only the blue eye displays the effect. In anatomy heterochromia refers to a difference in Coloration usually of the iris but also of Hair or Skin. The effect is still more pronounced in humans and animals with albinism. Albinism (from Latin albus, "white" see extended etymology) is a form of hypopigmentary Congenital disorder, All forms of albinism involve abnormal production and/or deposition of melanin.
Red-eye effect is seen in photographs of children also because children's eyes have more rapid dark adaption: in low light a child's pupils enlarge sooner, and an enlarged pupil accentuates the red-eye effect. In ocular physiology adaptation is the ability of the Eye to adjust to various levels of darkness and light
Similar effects, some related to red-eye effect, are of several kinds:
The red-eye effect can be prevented in a number of ways.
If direct flash must be used, a good rule of thumb is to separate the flash from the lens by 1/20 of the distance of the camera to the subject. For example, if the subject is 2 metres (6 feet) away, the flash head should be at least 10 cm (4 inches) away from the lens.
Professional photographers prefer to use ambient light or indirect flash as the red-eye reduction system does not always prevent red eyes, for example if people look away during the pre-flash. In addition, people do not look natural with small pupils, and direct lighting from close to the camera lens is considered to produce unflattering photographs.
Red-eye reduction techniques will be less effective when photographing people with dilated pupils.
Various graphics editing software packages have functions to remove red eyes from digital photographs. A raster graphics editor is a Computer program that allows users to paint and edit Pictures interactively on the computer screen and save them in one Some have automated this process, and can apply it to many photos at once. Red-eye removal is also built into many popular consumer programs like Microsoft Windows Vista Photo Gallery, Apple's iPhoto and The Gimp. Windows Photo Gallery is a photo management tagging and editing tool that is included in Windows Vista. iPhoto is a software application made by Apple Inc exclusively for their Mac OS X operating system The GNU Image Manipulation Program, or GIMP, is a free Raster graphics editor used to process digital graphics and photographs The downside to fully automatic software-based red-eye removal is that it is only accurate to approximately 75%.