Rotlichtmodus

Rotlichtmodus, also known as "red-light mode" in English, refers to a feature found on some electronic devices, particularly cameras and smartphones, that modifies the display to emit primarily red light. This mode is often employed to preserve night vision or to minimize sleep disruption. By using predominantly red light, which is less disruptive to the eye's photoreceptors compared to blue or white light, users can continue to see their devices in low-light conditions without significantly impairing their ability to perceive their surroundings in darkness.

The physiological basis for this functionality lies in the human eye's scotopic vision system, which is responsible for vision in low light. This system is more sensitive to longer wavelengths of light, such as red, and less sensitive to shorter wavelengths like blue. Therefore, a red-shifted display can be viewed with less visual strain and less interference with the natural dark adaptation process of the eyes.

In photography, rotlichtmodus might be used in darkrooms or during astrophotography to allow photographers to check settings or observe their equipment without ruining their night vision. On smartphones, it is often integrated into night mode or dark mode settings, or offered as a separate option to reduce eye strain before sleep. Some medical and scientific applications also utilize red light for specific observational purposes where maintaining dark adaptation is crucial. The implementation and availability of rotlichtmodus vary across different devices and operating systems.