Low frequency red light is used in Dark rooms because it does not expose the film, this is because the red light has low energy.
Explanation:
Red light is used as a safe light in the dark room because it has lowest energy and cause least damage to the photosensitive material used in photographic plate.
Among the lights of visible spectrum, violet has the highest frequency thus highest energy and red light has the lowest frequency and lowest energy.
Wavelength being inversely proportional to frequency ,is highest for red light and lowest for violet light.
The frequency and energy level of the colors decreases as: Violet> indigo>blue> green> yellow>orange>red.
