Editing Red-eye effect (section)

{{Short description|Photography appearance}}
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{{Use American English|date=January 2025}}
{{Use dmy dates|date=January 2025}}
[[File:BoldRedEye-corrected.jpg|thumb|upright=1.3|alt=A photograph of a human with the red-eye effect and its correction right next to it|A demonstration of red-eye correction]]
The '''red-eye effect''' in photography is the common appearance of red pupils in color photographs of eyes. It occurs when using a photographic [[Flash (photography)|flash]] at low lighting or at night. When a flash passes through the eyes and rebounds at the back of the eye, it causes a [[red reflex]] in an image, turning the subject's eyes red. The hue is mostly caused by a high concentration of blood in the [[choroid]]. The effect can also be influenced by the near proximity of the flash and [[camera lens]]. In children, a different hue red reflex, such as white or yellow, may indicate an illness. In animals, a similar effect could cause their eyes to change colors in photographs.

The effect can be avoided physically by instructing the subject to look away from the lens, increasing the brightness of the photographic location, or moving the flash further away from the lens, or digitally by using the red-eye correction option on [[digital camera]]s or by removing the effect in editing software. Scholars have developed a number of red-eye detection techniques to improve digital red-eye removal.